Abstract
The purpose of this article is to analyse British diplomats’ methods for intelligence collection and conveyance relative to the war effort in west Germany during the Seven Years War, highlighting that British intelligence networks on the continent were both extensive and effective in procuring intelligence. This intelligence dealt with news on the motives and intentions of enemy courts, as well as the movements, numbers and preparations of enemy armies prior to a campaign. British diplomats utilised various methods such as correspondence and agents to acquire intelligence, with their networks being more effective than their enemies throughout the Seven Years War.
Introduction
At the height of the Seven Years War, on 3 June 1760, Colonel John Clavering was sent to reside in the Landgrave Frederick II of Hesse-Kassel's court, an ally of Britain in Germany. In the instructions provided for Clavering, the chief of these was his mission to ‘carefully observe & endeavour to penetrate into the Views & Designs, which any Foreign Powers may be endeavouring to carry on at The Landgrave's Court’. 1 This instruction perfectly highlighted the dual role British diplomats had in Europe during the mid-eighteenth century. While their formal role was to conduct diplomacy with foreign ministers, a chief portion of their work consisted in the acquisition and conveyance of intelligence on enemies and allies back to British ministers. The purpose of this article is to delineate British diplomats’ methods for intelligence collection and conveyance pertaining to the west German theatre of war during the Seven Years War, 1756–1763. This article will highlight that these networks utilised numerous means of collecting intelligence, and were, on the whole, effective at procuring intelligence compared to their opponents. Furthermore, this article will display evidence to suggest that this intelligence had the potential to affect Allied operational and strategic level decision-making.
This intelligence dealt with news on the motives and intentions of enemy courts, as well as the movements, numbers and preparations of enemy armies prior to a campaign. It utilised both correspondents who acquired intercepted letters and précis of intelligence, as well as agents on the ground for surveillance on enemy movements and numbers. Furthermore, intelligence from one source was utilised to corroborate intelligence in another source, indicating that intelligence gathering was generally effective. This article will generally focus on the intelligence gathered relative to the Allied campaigns in west Germany. Therefore, a special focus will be placed on the British diplomat George Cressener, who was situated in Cologne and Maastricht, and whose intelligence was the most valuable to the Allied army's war efforts in that region. However, other diplomats and agents will also be consulted, such as Philip Yorke in The Hague, Richard Wolters in Rotterdam, Emmanuel Mathias in Hamburg, and Walter Titley in Copenhagen, whose intelligence to a lesser degree was also valuable to the war effort in west Germany. 2 All this intelligence would be delivered to British ministers back in Britain, particularly the Secretary for the Northern Department, who for most of the war was Robert d’Arcy, 4th Earl of Holdernesse, as well as the leader of the Allied army, Prince Ferdinand of Brunswick and his secretary Christian von Westphalen. 3
The sources utilised in this article were those composing the diplomatic and ministerial correspondence of the State Papers held at the National Archives and the Egerton Manuscripts held by the British Library in London. Cezary Taracha wrote of his experience that ‘usually the primary source materials form a part of an enormous volume of mail… Hence, it takes a lot of time before a valuable piece of information can be encountered’. 4 This was the same process I encountered, as with no previous research attempted in this area, thousands of letters by diplomats and ministers needed to be discovered, photographed, read and transcribed, in order to extract the few portions of valuable knowledge in order to build an understanding of how these networks functioned.
Intelligence in the eighteenth century as a whole is an understudied topic, with historiography rather focusing upon the periods both before and after.
5
The best articles that have dealt with eighteenth-century intelligence come from recent works by Matthijs Tieleman, Matthias Pohlig and Cezary Taracha, highlighting that there has been a renewed interest in eighteenth-century intelligence gathering in the past few years.
6
Pohlig's work dealt with the utility of intelligence during the War of the Spanish Succession, Tieleman's article addressed the topics of postal services and their uses for British and American spy networks during the latter half of the eighteenth century, while Cezary Taracha's
Diplomatic Intelligence Collection
Intelligence Acquired From Letters
One of the most valuable sources for the collection of intelligence were European post offices, which were commonly utilised for the acquisition of letters. 7 Tieleman notes how contacts within the Dutch postal service allowed Richard Wolters to ‘peruse and take the needful [letters] out’, copying the valuable information in these letters, and then returning them before they needed to be sent out. 8 This was a common practice for most British diplomats. George Cressener, in his position as diplomat to the Free Imperial city of Cologne, obtained the support of the Cologne postmaster, who allowed him to collect numerous letters on the movements and intentions of the French army. Cressener had likewise become friends with the postmaster of Liège when occupying his diplomatic position as resident in that city during the War of the Austrian Succession, 1740–1748. He wrote to Holdernesse on 17 May 1760, how he had previously ‘found it necessary’ to make the postmaster Mons. Lantermange his friend, and that this friendship, most likely maintained through pecuniary means, enabled him to secure his own letters, as well as obtaining ‘an account of what suspected letters passed by his office, of the persons who kept a correspondence with the French’. 9
Cressener came from a family of lower nobility, whose main branch lived in Essex. George was the youngest son, and so plied his trade in London. This relatively low social ranking compared to other British diplomats, may have given Cressener less qualms when undertaking the nefarious work of spy craft, something postulated by Marshall as having been evident in diplomats during the seventeenth century. 10 Cressener was an intriguing character; having fallen heavily in debt due to the South Sea Bubble after the creation of a successful grocery business, he had spent nearly two decades on the European continent, potentially in a trading capacity, as he attempted to negotiate a return home with his creditors. 11 His contacts across Europe perfectly placed him to conduct intelligence work for the British government during the war of the Austrian Succession, where his positioning in Paris, Brussels and Liège reaped significant rewards for British intelligence gathering. Having secured a formal position as a British diplomat in 1748, Cressener's employment in Cologne prior to the Seven Years War, was undertaken with the aim to remove him from Liège after his intelligence activities had incurred the wrath of the local ministry. 12 However, it turned out to be an assiduous move by the British ministry. He took up his role in September 1755, when increasing conflict between Britain and France began to threaten peace on the European continent; therefore, his place at Cologne would enable him to accrue intelligence on France's aims relative to undertaking any moves towards Hanover.
During the course of the Seven Years War, Cologne became a focal point for the French quarters upon the Rhine. Furthermore, it acted as an important postal hub for communication across western Europe; this enabled Cressener to intercept many French officers’ letters, as well as those of important princes of Germany and ministers of France. Through an analysis of Cressener's correspondence, I have been able to identify several important individuals such as Marshal d’Estrées’ aide-de-camp, the Electors of Palatine and Cologne, as well as an unspecified chamberlain of one of those Electors, Marechal de Camp Mons de la Touche, Colonel Louis-Auguste Baron de Planta de Wildemberg, and an endless list of unnamed officers of varying ranks within the French army. 13 One factor which enabled this was the freedom of the Cologne post, which was not part of the Imperial Reichspost controlled by the Thurn und Taxis family. 14 As such, Cressener could more easily send and receive letters without being affected by Imperial agents, a luxury he would not have when he was forced to move to Maastricht later in 1759.
The quality of the information Cressener pulled from intercepted letters throughout the war was of significant value to the Allied army in Germany. For example, in a letter sent to Holdernesse on 26 April 1760, Cressener wrote about the details he had gained from letters from Mainz, which reported that the French army under Marshal Broglie was adopting new methods in order to quicken their marches, including the minimisation of clothing, paraphernalia and extra horses. Meanwhile, a second letter communicated by Cressener on 11 June 1760 to Holdernesse, contained information regarding a letter by a French general to his friend in Cologne (whose identities were kept secret by Cressener), the letter informing Cressener of the rigorous marching training that was being undertaken at the French camp of Nider Seltz in order to make the French army quicker. All these innovations would become the bedrock of French military improvements undertaken by Marshal Victor François de Broglie, and would influence later developments during the French Revolutionary Wars. 15 These intercepted letters were most likely priceless to the Allied army, as they would have the potential to influence Ferdinand's strategic planning. While we have no existing written evidence to confirm whether this intelligence factored into Ferdinand's planning, we know Cressener forwarded this information on, as he clarified this in his letter to Holdernesse; as such, it is fair to assume that if this intelligence reached Ferdinand, it would have factored into his preparations. The quantity of letters Cressener could obtain was astonishing. For example, he reported to Holdernesse how he had acquired 30 different letters from varying officers in the French/Imperial army containing information about the battle of Rossbach and its consequences. 16
Another method of obtaining information from post was the use of agents employed by the diplomats, who would send a précis of information obtained from letters or copies of the original letters by high-ranking enemy officials. These agents would have either been local postal workers who were bribed to provide these letters, or diplomats’ own agents inserted into the enemy's postal system in order to acquire the letters. The correspondence for each diplomat usually centred around one chief correspondent who would send a packet of letters at a regular rate depending upon where they were situated. It would seem unwise to rely upon one agent to accumulate all relevant correspondence, however the quantity and quality of the letters from these correspondents indicated that the system was usually successful. Yorke communicated to Holdernesse his ‘regular correspondence’ from an unnamed agent situated in Paris, who would provide a bi-weekly précis of letters from people such as the Secretary for Foreign Affairs the Abbé de Bernis and later Étienne François de Choiseul, Duke of Choiseul, the French foreign minister Antoine Louis Rouillé, and several French generals. Yorke also had another agent positioned in the fortress of Wesel, an important fortress in Westphalia during the Seven Years War, who would provide him with the correspondence from the Swiss governor, Rodolphe Comte de Castella. Walter Titley also relied upon one chief correspondent, receiving a regular précis of letters and information from an agent inserted into the court of Sweden at Stockholm, while Richard Wolters employed a correspondent in Paris for 600 pounds per year, who acted as the centre point for a correspondence network that pooled information to send to Wolters.
17
There is little evidence for the methods these agents utilised to acquire these letters; this author supposes that they arranged it in the manner British agents would obtain letters from other postal services, either bribing postal workers to observe certain letters, or if they were employed in the postal service themselves, removing certain letters to copy before re-inserting them. This correspondence network would usually provide intelligence of significant value, especially for the preparations conducted by the Allied army, such as when Yorke obtained and forwarded the French Marshal Louis George Erasmé de Contades' campaign plans in his letters of the 6 and 12 May 1759, which led to the Battle of Minden, 1 August 1759.
18
When the French army later followed the same dispositions and movements laid down in those plans, Yorke later vindicated this intelligence collection in a letter of 15 June 1759 to Holdernesse, having stated: I can’t help begging your lordship to recollect how exactly the present conduct of the French, & the route they have actually taken, tallies with the advices I have had the honour to send you for some months past; I take the liberty to mention this because it is a sort of a security for the truth of many other things contained in them, & which at first sight appear very dubious & sometimes forged.
19
While in Paris in 1746, Cressener acquired the services of a member of the French court, who provided him with a regular correspondence on information within the French court in return for a regular subsidy of 500 guineas a year. 20 Cressener rose to the attention of the British ministry during the end of the War of the Austrian Succession due to his acquisition of this spy. The work undertaken by this spy enabled valuable intelligence to be provided to the Duke of Cumberland on campaign in the Dutch Republic. However, at the end of the war, the Duke of Cumberland's failure to provide this spy with a proposed £2000 monetary reward saw the spy end his correspondence with the British. When Cressener moved to Liège in 1755, he once again resumed correspondence with him, providing £1400 of his own money to induce the spy to once again provide intelligence. The French spy commented to Cressener that his outlays regularly exceeded the amounts given to him by the British, that ‘the expence in conveying the intelligence (as nothing could be trusted to the post) would very near eat up the money paid me quarterly’, and that it was only his trust in Cressener that saw him continue his intelligence work with the hopes of a sufficient remuneration at the end of the war. 21 Unfortunately, I have not been able to identify the name of this French spy, as it is never communicated in any letters I have seen so far, nor have I been able to make an educated guess on his identity so far based upon the evidence.
This spy was of substantial value to Britain and the Allied army during the war, with his correspondence being lengthy and numerous, an extensive report reaching Cressener every few weeks. He wrote on the strategy, finances, appointments, recruitment and logistics of the French forces, as well as the political machinations of several court members, which were usually pertinent to Prince Ferdinand's and Britain's war plans. This information was obtained from letters he had seen, or through private conversations with several members of the French court, including, most importantly, the French war minister Marshal Belleisle. He utilised British money as well as his own finances, to hold dinners and provide gifts which cultivated friendships throughout the French court, who would either inadvertently or knowingly (depending on the person) provide him with intelligence.
Care and precaution were taken in ensuring secure channels of conveyance were organised to transmit the spy's correspondence to Cressener. For example, when the French court moved to Compiègne, the French spy wrote to Cressener on 23 July 1757, how he had been prevented in writing to him for a considerable portion of time, in order to prepare a safe system of conveyance, as ‘extraordinary precaution’ was needed in order to not be discovered. 22 Pains were taken to ensure the identities of correspondents were never compromised. Neither Holdernesse nor any member of the British ministry knew of the identity of the several correspondents, which was only known by the diplomats. When identities were communicated, ministers were impressed with the need for absolute secrecy, such as when Cressener begged ‘this intelligence may be kept as secret as possible’ as ‘if it is ever discovered from whom it comes, it will be his ruin’, when writing about intelligence acquired from Doctor Baylies in the court of Prussia. 23 Diplomats’ letters to Holdernesse usually described the individuals as their ‘regular correspondent’, which was how Holdernesse referred to them in his own responses. This precaution over correspondents bore fruit when Cressener was thrown out of Cologne by the French governor on 16 March 1759. Cressener's French spy wrote to him detailing how he had been unaware of the steps taken to remove Cressener until the 8 March 1759, and related the ‘anguish I lived under’ until he discovered in a letter from Cressener on the 18 March 1759, that Cressener did not keep any papers in his possession that revealed his name, and therefore there was no evidence to indict him. 24 In fact Cressener believed his network of correspondence so secure that he did not believe the French had captured a single letter to either Lord Holdernesse or Prince Ferdinand, and that they could ‘only suspect, not prove the correspondence’ he was carrying on. 25 Though this sounds a bombastic opinion, the lack of information the French had on Cressener's network suggests that for the most part his opinion had some truth. Testament to this, Cressener's spy remained undiscovered throughout the war, and continued to provide intelligence for Britain for several years after the Seven Years War.
Britain's diplomats, chiefly Cressener and Yorke, also undertook measures to either acquire the services of individuals or install their own agents into the French army campaigning in Germany to provide a correspondence on the plans and preparations being conducted by the enemy. Prior to Prince Ferdinand's offensive over the Rhine in the summer of 1758, Ferdinand had written to Cressener on the 12 May 1758 asking him to organise a system of local correspondents who could provide information on the movements of the enemy: Find out proper persons in every town or village, where the French are quartered in this Electorate, and in the Dutchy of Juliers, to receive from them daily advice of whatever passed in their districts, to make journals of the whole, & transmit them to his highness.
26
Cressener had a poor opinion of this plan, stating that he could not develop this network as the inhabitants of the territory were all ‘Catholicks and Bigots’ and therefore could not be relied upon; this prejudiced comment was most likely influenced by his past negative involvement with the Bishopric of Liège's authorities, as well as his experience of the Catholic population of Cologne's rioting against Protestants in early July 1757, in which event he was forced to remain hidden in his house ‘whilst the madness reigned so strong’. 27 Cressener also stated in his letter that ‘the Post Master here is entirely devoted to the French, [therefore] the receiving and conveying such advices would be exposed to many difficulties and could not subsist long, without being discovered’. 28 This last statement from Cressener is a puzzling comment, as he seems to be refuting his letters to Holdernesse in which the Cologne postmaster helped Cressener to acquire post, which begs the question whether he was talking about the Cologne postmaster or another one in potentially Düsseldorf. Ultimately, these statements indicated that contrary to popular opinion, Cressener believed that not all of the German people were sympathetic to the Allied army. 29 Instead of instituting Ferdinand's proposed plan, Cressener introduced one of his agents into the service of the French Chief Commissary of War, in order to provide himself with logistical intelligence through letters. Cressener indicated to Holdernesse that whenever he wrote in his letters to him the words ‘I hear’, which were underlined, this would indicate this channel of intelligence. This enabled him to impart that this intelligence was trustworthy while not risking the identity of the correspondent. 30 Numerous subsequent letters from Cressener to Holdernesse which divulged important French logistical information throughout the Allied Rhine offensive, came from this channel. This also highlighted how while Prince Ferdinand could suggest steps for Cressener to acquire intelligence, he had no authority in which to order a British diplomat to follow his commands. While Ferdinand may have led the Allied army, which included British troops, and was a part of the wider British war effort, he lacked authority to organise and wield British intelligence. These networks were rather under the authority of the British ministry. Meanwhile, Yorke wrote to Holdernesse on 22 May 1759, how he had managed by way of bribery to induce a French officer in the army at Düsseldorf to maintain a regular correspondence of the French army's movements, transmitting money to him more regularly in order to encourage the correspondence. Yorke subsequently applied to Ferdinand to provide a secure channel with which he could easily facilitate payment for information. 31 This spy brought valuable information on the movements and preparations of the French army, including their logistics situation during the 1759 campaign.
The Use of agents
Diplomatic intelligence did not depend entirely upon correspondence and appropriated letters. George Cressener, Richard Wolters and Joseph Yorke regularly utilised agents in the field to collect information on the movement and numbers of enemy troop formations. Wolters' and Yorke's agents usually undertook surveillance missions to identify French troop and naval preparations along the French coasts, in order to provide forewarning of an amphibious invasion of Britain. Cressener's position behind the Rhine, first in Cologne and then in Maastricht was more valuable to the Allied army in Germany, as it enabled him to send his agents along or near the roads that French forces would travel to the respective theatres of operations. These agents enabled Cressener to gain visual confirmation of the numbers and movements of the French forces advancing toward the Allied army, and provide this information to Prince Ferdinand. A letter from Cressener to Holdernesse on 30 April 1760 highlighted how he had sent his agents on the road to observe the Scottish and Irish regiments in French service advancing to the front. The letter indicated how these agents would be utilised, and the specific instructions Cressener provided them with in order to maximise the quality of their intelligence gathering: I recommended to them to carefully count the company's in marching in, and out of the towns, to inform themselves of the private men of the force of their company's, as well as of the sergeants and corporals where it could be done with safety by wine, or money.
32
This indicated that the agents were furnished with money in order to bribe non-commissioned officers into providing details on the status of their companies. This money would have been provided by the diplomats who would have then filed the accounts for expenses. A perusal of Richard Wolters’ letters to Holdernesse indicate that he regularly enclosed his ‘accompt of disbursements for secret service’ every quarter year, which were drawn upon William Davis at the Treasury. 33
Cressener would regularly utilise agents in the above manner to collect accurate information on enemy troop numbers. For example, in his letter to Holdernesse on the 7 April 1758, he detailed how he had utilised three different agents to count the men in the first battalion of Royal Suédois, in order to obtain as accurate a record of the numbers in the battalion as possible. 34 This he did for every battalion that passed through the region he operated in. These numbers were regularly tabulated and sent on to both Holdernesse and Ferdinand. This knowledge of enemy numbers was in direct contrast to French intelligence, which regularly lacked accurate information on the Allied army's numbers, Cressener himself extolling this opinion in his letter to Holdernesse on 3 July 1758, writing that the French were ‘very ill served with intelligence’. 35
Cressener utilised his agents to determine whether the information he had received through letters was accurate. These agents were sent to different cities in the Empire to obtain information through surveillance, in order to corroborate what had been written in letters from Cressener's contacts. For example, when one of Cressener's correspondents at Bonn reported in a letter that the French General Charles Prince of Soubise had travelled there at a period of fraction between the French court and the Archbishop-Elector of Cologne, Cressener wrote to Holdernesse that he had ‘sent one I can depend on to Bon to let me know the truth’ to observe whether Soubise had been ‘charged with any commission to the Elector’. 36
Agents would also be utilised to travel to a region in order to inspect the preparations of the French army. The best example of this is described in Cressener's letter to Holdernesse on 18 April 1758, where he detailed how he had sent an agent from his cell in Liège to travel the Meuse river area, whereupon he discovered three bridges across the river, and that the French army had prepared ‘two very large houses there, one is designed for the post house and treasury, the other for a store house and that they intend to form magazines in that country’. 37 Since the position of supplies and magazines gave a clear indication of where an army would be consolidating, and identify what route it would take, Cressener's agents were invaluable in discovering the enemy's intentions to defend the Rhine region, in a period when Ferdinand needed as much information to prepare for his offensive across the Rhine. The work undertaken by Cressener's agents ensured he obtained a blanket coverage of surveillance over the territory of the west bank of the Rhine, enabling him to achieve complete intelligence superiority over the French.
Letters from diplomats indicate the mercenary nature of agents during the period. Several letters from Yorke, Titley and Wolters to Holdernesse explain how individuals had offered their services to either provide correspondence or surveillance measures for a price. Diplomats would not always accept the services of these agents without the approbation of the Secretary of State for the Northern Department, especially if the sum asked for was especially large. For example, Wolters wrote of a person who was ‘very fit to give good intelligence’, but since his price was of 2400 livres tournois per annum, Wolters could not ‘swell my accompts with that article unless I have fresh orders from your lordship for that purpose’. 38 One individual worked for Wolters on a trial period. He travelled France, observing French military preparations, whereby the quality of the intelligence he acquired would determine whether he continued in Wolters's employment. 39 Several individuals seem to have also worked on a ‘no contract’ basis, with an agent who had worked for the British in 1744/45 reapplying to Wolters in 1757 to provide intelligence on France, supplying a specimen of intelligence from an excursion he had undertaken. 40 Wolters indicated that his offer should be accepted as his intelligence had previously been valuable.
The acquisition of intelligence, and the creation of secure intelligence networks were enhanced by the diplomat's judicious ability to form friendships with individuals who were on the opposing side, especially those who had been friends before the Diplomatic Revolution in 1756. For example, the aforesaid acquisition of the support of the Liège postmaster Lantermange was enabled by Cressener's friendly manner, as well as his undertaking of several tasks that would procure his good opinion of him. In 1750, the court in Brussels removed Lantermange's rights to a piece of hunting land his ancestors had purchased from the Emperor Charles VI with 20,000 florins. Cressener saw a chance to gain favour with this, as he applied to General Károly József Batthyány of the Empire for help, who according to Cressener ‘promised me much, but did little’, which ‘exasperated the postmaster against the court of Brussels, and made him my friend, from the proof he had of my endeavour to serve him’. 41 Cressener enhanced this good opinion during his visit to Brussels in 1755, when he applied to Prince Charles of Lorraine, who in turn applied to the Emperor, ensuring the return of the hunting lands which secured Lantermange's friendship for Cressener. Furthermore, in 1757, Cressener was able to build a connection with the Papal Nuncio to the Elector of Cologne, Niccolò Oddi, whose conversation provided intelligence Cressener had not heard on French troop movements in Hesse in October 1758. 42 Their strong friendship also ensured the secrecy of Cressener's conversations with Oddi, as Oddi would not give up the details of their talks to the Elector of Cologne when he demanded it of him. 43 Oddi could be relied upon to undertake tasks as well, such as when the French military governor of Cologne, Monsieur Torcy, imprisoned the British diplomat Edward Blakeney in 1759. Cressener applied to Oddi to persuade Torcy to release him; while this was unsuccessful it showed Oddi was willing to undertake tasks for Cressener. 44 Edward Blakeney had been travelling to Nice to take up his position as British Consul in that city, for relations with the Duchy of Savoy. The French had feared that Blakeney was travelling to Nice in order to organise a scheme upon the coasts of Provence. 45 Prior to Blakeney's imprisonment, Cressener advised him that ‘if he had anything of consequence in his pocket book to seal it up, and leave it with me’, though Blakeney attested to Cressener that he had nothing to hide. 46 This suggests that Cressener may have thought Blakeney would have gathered intelligence as he crossed Europe, in a similar manner to gentlemen travellers during the Tudor period. 47
Another friendship which Cressener cultivated was with the Dutch diplomat to the Elector of the Palatinate, Carl Friedrich von Wartensleben. 48 Wartensleben's correspondence provided Cressener with intelligence on the French army around Frankfurt, during Wartensleben's residence in Mannheim. 49 Wartensleben's assistance was part of the reason why Cressener advised being sent as diplomat to the Archbishop-Elector of Mainz after he was evicted from Cologne, as he stated he would be ‘in the middle of the French army and shall have all the assistance Count Wartensleben can give, which will be of consequence now’. 50 Wartensleben's news, though infrequent, usually brought knowledge of troop movements and numbers and sometimes included intelligence of secret plans.
Countermeasures
The success of allied intelligence-gathering was so significant that their enemies were forced to undertake several measures in their attempts to disrupt the networks. These measures were chiefly directed at George Cressener, as his position in enemy-held territory enabled more direct steps to be taken against him. In Cressener's letter of 13 March 1759, he detailed how Mons Torcy, the French governor, was ordered by Marshal Belleisle, the war minister, to escort Cressener and the Prussian envoy Christoph Heinrich von Ammon from Cologne, due to the correspondence they were carrying out. 51 Cressener's enemies were aware of the dangers he could pose if left to continue his correspondence behind enemy lines, with the court of Vienna informing that of Versailles how he had been ‘a person who had been very useful to them in the last war’, exhibiting how extensive and successful Cressener's network of intelligence was. 52
While the French had a garrison installed in Cologne, they had no legal power with which to throw Cressener and von Ammon out of Cologne. As both of these ministers were in Cologne to serve as diplomats, especially in von Ammon's case as the Prussian envoy to the Circle of Westphalia, this action by the French indicated they were willing to upset the diplomatic framework in order to counter Allied intelligence. The French actions elicited strong condemnations from Britain against the violence ‘offered to the King's minister’. 53
Another measure the French took to limit the efficacy of Allied intelligence was the seizure of post. Once French armies began an offensive into Germany, they would seize any letters that contained valuable information along the routes they were travelling. For example, Cressener's letter of 28 July 1757 detailed how ‘all letters that pass by Cassell, by Osnabruck or Hildesheim are opened, and stopt if they contain any thing of consequence’, and so any postal communication between him and the Allied army was cut off. 54 This was followed up in his letter to Holdernesse on 3 April 1758, whereby all the letters from Westphalia ‘came broke open to the Post House’, which indicated that the French were monitoring all post into Cologne in the hopes of identifying letters pertinent to Allied intelligence. This did not fully stop Allied intelligence through the post however, as Cressener detailed how he would endeavour to ‘find a safe conveyance’ to continue delivering letters to Britain and the Allied army. 55 Though Cressener never detailed this ‘safe conveyance’ to Holdernesse, most likely for security reasons, the fact that his intelligence continued indicated that this was successful.
The confiscation of Cressener's post was more easily facilitated once he had to move to Maastricht after 16 March 1759. As many of his letters had to travel through the postal hub of the city of Liège, which functioned under the Imperial Reichspost, orders were given to seize all post to and from Cressener. This secret order had been communicated to all the Postmasters of the Empire, with Lantermange passing on to Cressener's correspondent in Liège how the Prince of Thurn und Taxis had commanded ‘all the directors and post-masters to stop all letters directed to Mr Cressener, or wrote by him’.
56
Cressener was accused of retiring to Maastricht in order to continue his correspondence with the ‘enemy cabals’, and were directed ‘to dispatch all letters they may intercept to be sent to the Vice-Chancellor of the Empire’.
57
Lantermange took a risk in sending this information to Cressener, as the postmasters were enjoined ‘not to reveal this order to anybody, but to keep it secret, under pain of our displeasure’, and as such had put his ‘fortune, as well as liberty’ in danger by imparting this information.
58
The fact that these orders were only delivered in May 1760, a full year after Cressener had left Cologne for Maastricht, suggested the inefficiency in French and Imperial countermeasures to crack down on Cressener's network. Though Cressener wrote of these problems encountered in the Imperial post, this does not seem to have slowed down his intelligence gathering, as his intelligence continued to flow to British ministers and the Allied army, indicating he had several means of transporting his intelligence separate from Imperial influence, which he had earlier stated to Holdernesse on 14 April 1759: I have taken care to advise Prince Ferdinand of this, and of every thing that is come to my knowledge by so many different ways that some of my letters will certainly reach his highness, notwithstanding all the precautions the French take.
59
French authorities would also act against correspondents and agents conducting surveillance of areas. Though Cressener seems to have had little difficulty with his own correspondence networks and agents on the ground, British networks under Yorke and Wolters were not infallible. The system of acquiring correspondents who would provide a précis of intelligence relied upon the expertise of the agents in acquiring this mail. Either a mistake from the agent, or the vigilance of the enemy could lead to these agents becoming compromised. Both Yorke and Wolters communicated to Holdernesse how a diminishing return or cessation of information most likely portended that their correspondents had become apprehended. 60 From September 1759 onwards, Yorke detailed to Holdernesse how the quality and quantity of the intelligence acquired from his correspondent had significantly decreased, stating in a letter of the 21 September 1759, that he ‘writes very little of consequence’. 61 At the same time, Yorke wrote how his agent who surveyed the Low Countries coast had not written to him in a while, making Yorke write how he was in ‘a little in pain for him’, as the French authorities there had begun to become ‘very inquisitive there about all comers & goers’, due to their naval preparations for a proposed invasion of Britain. 62 Though this agent was not necessarily acquiring information specifically for the Allied army in Germany, this example highlighted that there were measures conducted by the French to combat British agents conducting surveillance, and that these measures were possibly re-doubled during certain periods in a specific theatre where they were of strategic importance.
In a letter of 7 December 1759, Yorke finally admitted to Holdernesse, that he believed his correspondence network from Paris had become compromised, as he wrote: I have received nothing of late from the person who used to give me those papers I took the liberty to send your lordship; he said he was ill a few days ago, tho’ I suspect the source he had them from is stopt; I shall know however soon what is the reason of his silence.
63
Though Yorke subsequently wrote to Holdernesse on the 28 December 1759, that he was ‘endeavouring to re-establish my correspondence, which had of late diminish’d in goodness, & will do my utmost to recover it & amend it’, Yorke was not successful in re-establishing the quality of the correspondence from Paris throughout 1760, as he lamented to Holdernesse on 3 December 1760, that he had been ‘remarkably unlucky in conveying intelligence to you’ that year.
64
Yorke ultimately provided an explanation for the breakdown of his network in a letter to Holdernesse on 6 January 1761, where he related how he had dropped his correspondence with this person as he had: Found for some time they ceased to be authentick, owing at first to the indiscretion of the person concerned, which made more caution observed, in the place they were taken from; & besides, that since the Duke de Choiseul came into power, & the [French] army in Germany has been new modelled, the person wrote to has neither so many nor so good correspondents, & is really ill informed, & upon this your lordship may depend; I don’t fail however to keep an eye to that quarter, & will omit no opportunity of renewing.
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Though this was a considerable blow to Yorke's acquisition of intelligence during the later part of the Seven Years War, this breakdown of his correspondence network only affected him, as the intelligence networks organised by Cressener, and to a lesser degree Wolters and Mathias continued to provide valuable intelligence for the Allied army throughout the war.
The British also had their own measures to counteract French attempts at setting up intelligence networks in Britain. Yorke stated in his letter to Holdernesse dated 2 December 1760, that the French were ‘ill informed from England’, and part of this was due to the work conducted by British diplomats in ensuring French agents sent from Europe could not build any networks there. 66 Yorke's letter of 5 June 1759 described how he had utilised one of the Royal Messengers sent to him to monitor the movements of a Mr Sichehaye, lately of the Brunswick service, but now travelling to England in order to build a network to procure intelligence for the French. 67 Yorke did not write how he had discovered this man, though he seems to have been tipped off. He had managed to acquire a ‘specimen of his hand writing, his name & seal with his arms’ and discovered that he was travelling under the name of Vallent. Yorke had instructed the Royal Messenger with him ‘to attend privately to him, & to learn his place of abode, as well as to know his figure’. 68 This indicated that the Royal Messengers were accustomed to undertaking surveillance tasks; for example, later in April 1761, Delaval the British resident in the Hague while Yorke was away, informed Lord Bute that a Mr la Borde, a French peruke maker in St James' Street was returning to England from France likely for espionage reasons, and that the King's Messengers knew him well and should therefore be utilised to watch him. 69
Conveyance of Intelligence
The Use of the Post
The chief medium by which British diplomats and spies conveyed their intelligence were through the conveyance of letters. These letters would either be ciphered or not, depending upon the value of the information and the secure nature of the channel being utilised. For example, Cressener, who felt secure in the channels of his conveyance at Cologne and Maastricht, rarely ciphered his letters, leaving this only for information of very high value. This is in contrast to Walter Titley's position in Copenhagen, where a significant portion of senior Danish ministers supported the French, which forced him to regularly cipher important passages of his letters as he knew they were likely to be intercepted. The use of ciphers was a valuable tool in eighteenth-century intelligence and had been built upon the developments from previous intelligence networks, especially those of the seventeenth century. 70
British diplomats were provided with three sets of ciphers throughout the war, each in pairs, one to cipher and another to decipher. 71 Those used in the Seven Years War used titles with designated letters coupled with a corresponding year, though those years never matched with the correct date. For example, after the war in 1764, Cressener was provided with the new cipher K, and the decipher L, with the corresponding date of 1759. These ciphers were composed of sets of numbers, usually four, which designated numerous different forms of information, such as a word, phrase, name or place. Furthermore, certain numbers were utilised to make the cipher more complex, and harder to break once intercepted. For example, the number 2465 in cipher K 1759, informed the reader to disregard the previous two sets of numbers. According to William Gibson, the British were adept at breaking French ciphers, utilising a department that was headed by the Bishop Edward Willes and his family, though it seems that there was only one French cipher, designated 1760, in British diplomats’ possession throughout the war. 72 This French cipher was sent onto Prince Ferdinand in order to enable him to decipher intercepted French letters. Ferdinand was extremely desirous of this broken French code and sent letters to Holdernesse thanking him for sending it on to him. 73
The main method of conveying intelligence was through the postal systems in use, that of the Imperial Thurn und Taxis post, the Free Imperial city of Cologne's post, the various north German states post or the Dutch post offices. 74 Unlike those of diplomats during the reign of Charles II, intelligence reports from British diplomats in the Seven Years War were far more concise. Rather than the extensive 12 pages, reports were usually around 3 pages long, and compiled every 3 or 4 days. 75 This matched the regularity of the postal delivery system. 76 Diplomats would leave the writing of letters until the post was nearly ready to be dispatched. By writing letters so late, this would leave little time for any enemy agent inserted into a post office to fully copy the letter. 77
Cressener needed to become creative in how he conveyed his letters through these systems as they would be travelling through enemy-occupied lands. When sending his letters from Cologne to either Amsterdam or Ostend, with Ostend at that time garrisoned by the French, his support from the Cologne postmaster enabled him to place his letters within the Italian packet that was transported to these cities, as Cressener was informed that the French never inspected the Italian packet.
78
Instead of ciphering, another measure was the use of methods of sealing the letters in a difficult manner to open, with wax. If the letter had become tampered with, then the recipient would know they had been opened, and would arrange a different channel of conveyance. For example, Cressener detailed to Holdernesse in his letter of 12 August 1757, how he had: Taken some pains to seal it [the letter] so as to make it's being opened difficult without your lordships perceiving it… if your lordship lets me know it has been opened, I shall avoid sending any thing in cypher that way.
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Intelligence from post reached Britain at differing intervals depending on the nature of the distance and the weather conditions. Depending on prevailing winds, ships could be holed up in harbours unable to leave, and therefore intelligence could take a significant period to reach the Secretary of State for the Northern Department in London. This was most pertinent to Walter Titley in Copenhagen, where the weather was usually bad, causing problems with letters travelling both by sea and road. 80 Furthermore, this could be the same for news from Cressener to Yorke, with Yorke regularly stating the weather impacted the arrival of news and intelligence along roads from Cressener in Cologne and from the postal hub of Hamburg.
Estafettes/Couriers
As post would have to travel through enemy-occupied land on its way to the Allied army, the postal system was not optimal for the delivery of this news. Therefore, Yorke and Cressener would utilise what they called ‘safe conveyances’ to the Allied army. These were most likely estafettes or express riders, who would be given sealed or encrypted correspondence to deliver to the Allied army on horseback. This system in itself was fraught with risk, as they would have to travel incognito through enemy land to carry this information. They regularly risked interception by French light troops, such as when Ferdinand's courier Ruel was captured by the French at Vechta, most likely on his way from the Dutch Republic, related in a letter from Mr Haenichen (Duke Louis of Brunswick's secretary) to Westphalen on 19 July 1759. 81 He managed to escape capture due to his guards becoming drunk, and continued on to the Allied army via Bremen. Another English messenger arrived at the Allied army having had to tear up all but one of the letters on him, in order to avoid them falling into the hands of the French. 82 These riders would also sometimes be Royal Messengers, who would bring letters from the Secretary of the Northern Department, and then would either bring back intelligence from the diplomats, or would be forwarded on to the army with intelligence. 83 Several messengers would crop up in correspondence, such as the English courier named Otto, indicating that they moved between Holdernesse, the diplomats Yorke and Cressener, and then onto the Allied army to Prince Ferdinand and Westphalen. 84
Utility of Intelligence
There is little evidence in the published letters by Westphalen, or any letter written by the army in the State Papers, that discussed how intelligence affected operational and strategic level decision-making. It is more likely that British intelligence was evaluated by Prince Ferdinand and Westphalen in person, so we do not easily see how campaign decisions were taken in the light of this intelligence. However, one identified instance in a letter gives an indication of the thinking process behind British intelligence affecting operational decision-making. During the Allied campaign on the west bank of the Rhine in the summer of 1758, the Allied army was manoeuvring against the French army, while an allied detachment under General Karl von Imhoff besieged the French fortress of Wesel. Westphalen sent a letter to Ferdinand, where he suggested Ferdinand could reinforce the main army from Imhoff's detachment, as Westphalen believed there was little evidence the French would detach forces across the Rhine to engage Imhoff and break the siege. This belief was formed from a few letters sent by Cressener on the 29 and 30 June 1758, which detailed intelligence from Cressener's agent inserted into the French commissary, as well as correspondence and Cressener's own agents that informed Westphalen that the French were in no position to advance forces onto the east bank of the Rhine, and that bridges built across it by the French were created simply to move their hospital to a safe location. 85 In this case, Cressener was close enough to the campaigning region to affect operational decisions with his timely intelligence.
Letters indicated that British intelligence networks were of significant value to the Allied army. Westphalen wrote to Haenichen how he feared that the expulsion of Cressener and von Ammon from Cologne in 1759 would be significantly detrimental to the war effort, as they were ‘counting heavily on this correspondence.’ 86 Yet Westphalen's fears were misplaced, as while von Ammon was forced to move to Münster, where his influence over acquiring intelligence was diminished, Cressener's move to Maastricht, not far from the cell he had developed in Liège, and still behind the French lines, enabled him to continue effectively supplying the Allied army with intelligence. 87 Furthermore, Ferdinand wrote to Cressener how valuable his intelligence had been in affecting Allied army strategy when leading up to the Battle of Vellinghausen, 15/16 July 1761, stating he had ‘reported to the King your precise correspondence, the numerous and useful services you've rendered to the army through it’. 88 Though this is a small pool of evidence, it is safe to assume British intelligence was valuable to Ferdinand and did affect his strategic and operational decision making. With further research undertaken in this area, we will be better able to identify to what degree the Allied army's decision-making was affected by British intelligence.
Conclusion
Ultimately, this article has shown to the reader the various methods deployed by British diplomats to acquire intelligence during the Seven Years War. These methods were on the whole largely successful in acquiring valuable information pertinent to the war effort in west Germany. Contrary to Richard Glover's poor assessment that British diplomatic intelligence gathering ceased to exist in times of war, British diplomats like George Cressener organised intelligence networks that operated in zones of operation. 89 While diplomats may have been further away from the conflict, they acted as the hub of this intelligence acquisition. Their networks spanned significant distances, and were able to survey large portions of enemy territory to acquire important information on the numbers, dispositions and movements of enemy troops.
British diplomats utilised a wide variety of means to collect information. Both acquiring correspondence through the perusal of mail, as well as intelligence from a précis of letters forwarded by valuable correspondents in enemy territory. Agents on the ground were also utilised to survey enemy preparations, providing valuable knowledge on the movements, numbers and dispositions of enemy forces that had the possibility of affecting Allied strategic and operational decision-making. Furthermore, intelligence from agents was leveraged to corroborate intelligence acquired from letters. While French countermeasures were employed to inhibit British intelligence gathering, such as the loss of Philip Yorke's correspondent in Paris in late 1759, on the whole, British intelligence continued to function well throughout the war, utilising numerous means in which to convey information both to British ministers as well as the Allied army in the field.
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author received no financial support for the research, authorship, and/or publication of this article.
