A Catalogue of Greco-Roman Comets from 500 B.C. to A.D. 400

The Samguk sagi (History of the three kingdoms), a work written c. A.D. 1145, covers the period 100 B.C to A.D. 930, and unlike the Chinese dynastic histories (see below), it contains no treatises on astronomy or the “Five elements”. The reports of comets are all found in the “Annals of the kings”, and comparison between these accounts and Chinese sources, where extant, show that most (but not all) of these Korean records were copied directly from the Chinese historians. Japanese sources are of no help for this early period because they do not begin to supply information about comets until the seventh century A.D.

For a recent synthesis of all of this evidence for ancient comets, see Kronk Gary , Cometography: A catalog of comets, i: Ancient to 1799 (Cambridge, 1999). Kronk's catalogue is the first to provide a comprehensive treatment of the various sources since that of Alexandre-Guy Pingre in vol. i of Cométographie (Paris, 1783). Pingre is still worth consulting despite the age of his publication because of his sound judgment resulting from his great skill as an astronomer and from his command of classical Greek and Latin. Often Pingre reaches the correct conclusion despite not having had access to any of the Babylonian evidence because it had not yet been brought to light, and despite knowing the Chinese reports only through a French translation of a late Chinese source that did not always preserve the fullest and best accounts.

See Bauer Brian Dearborn David , Astronomy and empire in the ancient Andes: The cultural origins of Inca sky watching (Austin, 1995). Brian Bauer informs me that to the best of his knowledge there is no comparable study for astronomy practised by the Aztecs.

This evidence is most conveniently consulted in the edition of Sachs Abraham Hunger H. , Astronomical diaries and related texts from Babylonia (3 vols, Vienna, 1988–96).

Stephenson F Richard Yau K. K. C. , and Hunger H. , “Records of Halley's Comet on Babylonian tablets”, Nature, cccxiv (1985), 587–92.

Yoke Ho Peng , “Ancient and mediaeval observations of comets and novae in Chinese sources”, Vistas in astronomy, vi (1962), 127–230.

There are, of course, exceptions such as the above mentioned report of Comet Halley in 87 B.C. (Ho no. 47), which seemingly gives either the wrong location (E, instead of W) or the incorrect month (Aug., instead of July).

For a summary of the findings of a careful study of the Chinese eclipse records conducted by Neasa Foley, under the direction of F Richard Stephenson at the University of Durham, see Ramsey J. , “A descriptive catalogue of Greco-Roman comets, from 500 B.C. to A.D. 400”, Syllecta classica, xvii (2006), 23.

For instance, two distinct, intermediary sources, one of which preserved fewer details from the imperial archives than the other, are likely to lie behind the astronomical records in the Qian Han shu [History of the former Han dynasty] composed c. A.D. 100 by Ban Gu. For a demonstration of this, see Stephenson F Richard , “The ancient history of Halley's Comet”, in Thrower Norman (ed.), Standing on the shoulders of giants (Berkeley, 1990), 231–53, pp. 238–9 with Fig. 13.3. Beck B. J. Mansvelt , The treatises of later Han (Leiden, 1990), 114, makes a tentative identification of one of those sources.

For a description of the imperial observatory, its chief officials (astronomer, astrologer, meteorologist, timekeeper), instruments (brass armillary spheres and sighting tubes), and place of observation (a tower or platform), see Needham Joseph Ling Wang , Science and civilisation in China , iii (Cambridge, 1959), 189–91, quoting from the Zhou li (Record of the rites of Zhou, composed in the second century B.C.).

Stephenson , op. cit. (ref. 9), 244. A silk manuscript discovered in a Han tomb dating to 168 B.C. shows us at first hand how detailed the primary Chinese sources doubtless were. It gives relatively full accounts of the heliacal risings and settings of various planets during the years 246 to 177 B.C., compared with which there is nothing on the same scale in the extant Chinese reports of ancient comets. See Loewe M. , “The Han view of comets”, Bulletin of the Museum of Far Eastern Antiquities, lii (1980), 1–31.

Barrett A. A. , “Observations of comets in Greek and Roman sources before A.D. 410”, Journal of the Royal Astronomical Society of Canada, lxxii (1978), 81–106.

Weifeng Zhuang Fixing Wang , Zhongguo gudai tianxiang jilu zongji [Complete collection of records of heavenly phenomena in ancient China] (Nanjing, 1988).

Some 14 out of Barrett's 64 objects were almost certainly not comets: Those in 174, 168, 134, 106, 100, 91, 76, 63, 56, 52, and 42 B.C. and in A.D. 162, 393, and 396.

I thank Anthony Barrett for welcoming my proposal to undertake this project when I consulted him to ascertain whether it would conflict with plans of his own. I also gratefully acknowledge his kindness in reading and commenting upon my work in an earlier draft.

Ramsey , op. cit. (ref. 8). Research for this publication was begun in 2005, when I was a visiting Fellow at Corpus Christi College, Cambridge. I thank the Master and Fellows of Corpus for making my stay such a productive one.

Gundel Wilhelm , “Kometen”, in Pauly F. Wissowa G. (eds), Real-Encyclopädie der klassischen Altertumswissenschaft, xi/1 (Stuttgart, 1921), 1143–93.

They are for the years B.C. 480, 410, 372/1, 48, 43, 31, 11, and 1; and for the years A.D. 10 11, 14, 115, 130, 192, 200, 364, 396, 398, and 402.

Significant departures from past catalogues will be found under the following years for the period B.C.: 481, 430,394, 350/49,346?, 174,169,135,104?, 88, 76, 53/2, 49, 45, 43, 42, 32, and 12; and for the period A.D., in the years 13?, 66, 117?, 132?, 191, 204, 351, 363, 375, 393, 398, and 400.

Where Ho's report of the Chinese/Korean evidence requires correction or can be supplemented, these revisions are provided: E.g. revised dates (A.D. 117 and 132) for Ho nos. 93 and 97–98; earlier and better sources for the comets of 87 B.C. and A.D. 204; and additional evidence for the comets of 135 and 119 B.C.

See Ramsey J. T. Licht A. Lewis , The comet of 44 B.C. and Caesar's funeral games (Atlanta, 1997), 73–74, for a discussion of the probability that two sightings a few months apart, such as in 44 B.C., are likely to concern the same comet.

Additional material will be found for the period B.C. under the years 481?, 467, 426, 394,372, 350/49, 344, 88, 87, 63, 45, 44 (24 additional texts in this year alone), 43, and 42; and for the period A.D. under the years 9, 13?, 54, 60, 66, 191, 336, 351, 363, 389, 398, and 400.

No comet attracted as much notice as “Caesar's Comet” of 44 B.C., which is reported, or alluded to, in 33 texts and on 4 different coin types illustrated in this catalogue. The next most frequently mentioned comets are the Claudian comet of A.D. 54 and the Neronian comet of A.D. 60: 10 and 11 notices apiece, many of which are provided by the contemporary observer Seneca (former tutor and later close advisor to Nero). Aristotle's “Great Comet” of 372 B.C. and the comet of A.D. 66 (Halley) hold the fourth and fifth places, being attested by 8 and 7 texts respectively.

We can determine the month, or range of months, for only three comets in this catalogue solely on the basis of information supplied by Greco-Roman sources: Those in 426, 372, and 44 B.C. In addition, the eclipse comet of Posidonius can be dated to 19 July, if, as argued, the relevant eclipse was the one in 104 B.C., and the “Torch of Timoleon” can possibly be assigned very tentatively to March of 344 B.C. (in which case it was not a comet but a meteor shower).

Stephenson , op. cit. (ref. 9), 250–2.

A comparable example of a gap of a year (or less in the case of Augustus) between a comet portending an emperor's death and the demise of the ruler is furnished by the comet of Feb. A.D. 336, which was regarded as foreshadowing Constantine's death (in May 337).

For instance, to give only seven, clear-cut examples of omission, the extant Chinese records fail to report the comets attested by presumably trustworthy Babylonian accounts for the years 210, 164, 163, and 110 B.C. and by the reliable testimony of Aristotle for the years 426, 372, and 341/0 B.C.

Menzel Donald Pasachoff Jay , Stars and planets, 2nd edn (Boston, 1995), 384.

49 comets having a magnitude >2 were visible in the northern hemisphere during the last 270 years (1701–1970) included in Hasegawa Ichiro , “Catalogue of ancient and naked-eye comets”, Vistas in astronomy , xxiv (1982), 59–102 (updated by Jansen J. , “Additions and corrections to I. Hasegawa catalogue”, Vistas in astronomy, xxxiv (1991), 1991–86). This total yields an average of 18.1 “bright” comets per century, a figure in line with the estimate of Stephenson, op. cit. (ref. 9), 234, based upon extant Chinese reports, that on average 20 such comets would be visible per century.

A figure based on reports in Hasegawa's catalogue (ref. 29). It is likely that at least a few of these fainter objects were noted because in Antiquity viewing conditions were far superior to what they are today (less pollution from particulates and urban lights). Also, in Antiquity human beings paid much more attention to the night-time sky because until Julius Caesar's introduction of a reliable calendar in 45 B.C., the risings and settings of the stars provided one of the chief means for regulating the sequence of seasonal activities.

In fact, the 43 comets observed the third century A.D. just happen to be the average number of naked-eye comets reported per century for the period A.D. 800–1700, when records become fuller. See Yeomans D. , “Comets, historical apparitions” in Maran S. (ed.), The astronomy and astrophysics encyclopedia (New York, 1992), 114–18, p. 115 and Fig. 2.

Not including the comet of 73? B.C. since that date is merely an alternative for the “eclipse” comet of Posidonius, already included in the count for the second century B.C. under 104.

The catalogue makes it easy to survey the nature and coverage of the sources by means of an Index Locorum. In that index, all Greek and Latin authors are listed in alphabetical order, the dates of composition are given, and next to the citation of each passage, the date of the comet (or other object) is provided, together with the Greek or Latin word(s) used to describe it.

Two of the reports by Seneca in particular (those for 147 and 135 B.C.: NQ 7. 15.1–2) appear to have been drawn from careful observations made most likely by a professional Greek astronomer who recorded the apparitions of those comets. Such detailed reports in the Western sources are the exception, however.

For the years 204, 203, 176, 169 B.C.

Obsequens is the sole Greco-Roman source for 166, 163, 137, 94, and 92 B.C.; Livy/Obsequens for 167 B.C. In only three of the years for which Livy/Obsequens is the only source, does evidence for a comet happen to be preserved in non-Western sources: For the years 204, 163, and 137 B.C.

For the years 32, 30, and 12 B.C. and the years A.D. 69, 132?, 204, and 218.

Grave doubt exists as to the reality of a comet in 216 B.C. and in A.D. 9, for instance.

The collection of yearly pontifical records in the Annales maximi is the chief archival source that may lie behind the report of portents, such as comets and meteors, in Livy (and by extension in Obsequens, who drew upon Livy). For a good brief summary of the present state of the question and modern bibliography concerning the presence of archival material in the Roman annalistic historians, see Bruce Frier, Libri annales pontificum maximorum: The origins of the annalistic tradition, 2nd edn (Ann Arbor, 1999), pp. v-xix.

The fullest extant version of this predictive literature on the astrological significance of comets is found in John Lydus (fl. c. A.D. 560), De ostentis 10–15b; cf. Hephaestio, Apotelesmatica 1.24.5–12; Servius, on Virgil, Aeneid 10.272.

E.g. Aristotle, Meteorology 1.6 343a26; ibid. 1.7 344M9; Aratus, Phaenomena 1092–93; [Theophrastus], De signis 2.34.

So, for instance, Kidd D. , edn of Aratus, Phaenomena (Cambridge, 1997), 557.

Yeomans Donald , Comets: A chronological history of observation, science, myth, and folklore (New York, 1991), 95, 99.