This book is a synthesis of a wide range of classical and non-European written sources with the relevant astronomical data and numismatic evidence to provide a description and discussion of 73 objects from antiquity that are, or may be, comets. Ramsey (hereafter R.) provides an explanation for how each object has been classified, which dates it may fall under, a summary of the existing arguments surrounding the object, and in some cases his own re-dating of the event. It is useful primarily for historians, but non-historians, such as astronomers, could find it instructive and interesting as well.
The purpose of the book is to provide a catalogue of comets from antiquity that is more thorough, detailed, self-contained and up to date than any of the existing comet catalogues. R. acknowledges his indebtedness to the works of Pingré (1783), Gundel (1921), Barrett (1978), Yeomans (1991) and Kronk (1999) in particular (pp. 3-5),1 and throughout the work he cites both arguments in print and a large number of historians and astronomers on whose expertise he has drawn through personal communication. The result is a catalogue that accounts for more current scholarship than any that precedes it. For all that R.’s work is detailed, including all the passages of classical texts in the original language and in translation, and even synopses of the Chinese, Korean and Babylonian evidence, it is still admirably brief and to the point, with few arguments taking more than a page or two to outline. Many are much shorter than this, and the longest by far — that of the comet shortly after the death of Julius Caesar in 44 B.C. — spans only 18 pages (pp. 106-125).
The introduction to the book (pp. 3-28) is thorough and clear, providing a useful overview of comets in antiquity and previous scholarship (pp. 3-4). R. discusses the features of his new catalogue, highlighting the inclusion of all the relevant sources in Greek and Latin and in translation, non-European sources (in translation), the symbols used so the reader can ascertain certain details about an entry at a glance, and the precision of his dating, which includes seasons, months and days, rather than simply years, for as many objects as possible. He continues with a discussion of the nature of the evidence, including an overview of the quality and limitations of the surviving accounts and the important corroborative evidence from the east, before going on to compare the different sources of information. He finishes the introduction with a discussion of the terminology used by writers for the different types of comet, including some statistical analysis of the evidence, as discussed below (pp. 24-8). Many of these features appeared in earlier comet catalogues; Schove & Fletcher (1984) listed each comet with a similar precision of date (including seasons and months, as well as years), while Barrett (1978) included texts and translations with each object.2 However, R.’s is the first catalogue to incorporate all of these features into a single corpus of material.
The next section of the book comprises a table summarising all the possible comets by date; this table includes the names of the sources the comet is found in, some information about the historical context and details of alternative dates offered in other comet catalogues (pp. 29-46). This is followed by two short sections explaining the symbols used in the main catalogue, and the abbreviations and glossary of terms (pp. 47-8), before moving on to the main catalogue itself, which comprises the bulk of the book (pp. 49-190). This is followed by two appendices; the first listing 22 objects that R. considers not to be comets (pp. 191-214), and the second detailing a single comet, that of Tigranes, which appears in numismatic evidence only and is of uncertain date (pp. 215-18). Finally there is a full Index Locorum, enabling the reader to easily find all the comets in, say, Livy, including the terminology used in each instance. This is followed by a very short index of the four instances of numismatic evidence (p. 233), and a sizeable bibliography.
Overall, this book is very useful, in particular because of the multiple different ways of accessing the material. The reader can locate a comet by the date, find all the comets in a particular source, can readily see whether there is corroborating evidence from non-European sources, get the basic information on the date of the comet, see whether it was Halley’s comet, check the date of the object in previous catalogues and review the sources, all without needing a library to hand. Additionally, the book is thoroughly cross-referenced, so should an issue be raised in one example, such as Livy’s and Obsequens’ tendency to use the word fax to describe a comet, then the text directs the reader to other examples where the same issues are raised. Thus it is not necessary to read through the entire volume, as the cross-referencing will direct the reader to other relevant material. The Index Locorum is of great value in this regard, but the lack of a general index ultimately limits the usefulness of the book to wider research; for example, it is difficult to search for all instances of comets coinciding with earthquakes.
R. does some interesting statistical analysis of the cometary data in his introduction, such as showing that 9 comets are associated with the death of Roman emperors and 17 with battles or wars (pp. 20-1), demonstrating that comets were more likely to be recorded with significant events than as isolated phenomena. The information he provides enable readers to perform their own analyses. This is a strength of the work, as by combining so many objects in a single place (8 more than in any previous catalogue for the same period), it allows other scholars the chance to analyse all the material and evidence for themselves. It also includes information that scholars would not normally have, and that does not appear in other comet catalogues, such as current astronomical information relating to the path of some of the comets, the timing of the full moon(s), and the size of the comet and its tail in the sky.
The discussion for each comet is brief by necessity, but usually coherent and convincing, engaging with the sources and the historical context, as well as the astronomical information. The value of the eastern evidence is clear, however, as of the 33 objects definitely identified as comets in the catalogue, 26 are corroborated by eastern evidence. It does appear from R.’s study that it is only through non-European evidence that we are able to confirm whether an observed object is actually a comet, but R. is cautious about using oriental evidence and stresses the ambiguous nature of the terminology and some of the main issues raised from studying these sources, which are primarily Chinese, are discussed in the introduction (pp. 22-4). In general, the oriental evidence is presented only in a translated summary, and its historical context is not discussed, so the interested reader has to consult the bibliography for further information. Similarly, there is no discussion of the problems of calibrating the oriental chronographic system(s) with those of ancient Greece and Rome, which might have been beneficial to those readers not familiar with oriental history. R. understandably tends to be more willing to put a date to a comet if there is an oriental account from approximately the same year to corroborate it, but this is slightly problematic because each ancient date — oriental or occidental — is converted into the Julian calendar before discussion, and therefore any errors in the chronographic tradition may be hidden, and compounded. A fuller discussion of the accuracy of both chronological schemes, and how they relate to one another, would have been useful.
There is an interesting argument running through the case studies themselves; R. argues convincingly, albeit from somewhat sparse evidence, that the nature of comets as omens presaging wars and pestilence arose in the first century B.C. (pp. 50-1, 95-7). He suggests that the Marian-Cinnan civil war may have been the stimulus for this because of the lack of evidence that comets were seen as omens prior to this time (pp. 95-7). This might have benefited from being written as a separate section in its own right, as the argument is spread between several comet entries, those of 481, 430 and 87 B.C.
It would have been helpful for R. to have included a short section on astronomy, including a discussion of the limits and techniques of ancient observation, and the terminology and basic physics of modern astronomy, as time and again points are raised or terms are used that could have been explained in brief elsewhere. For example, he uses terms such as ‘perihelion’ (closest approach to the sun) and ‘declination’ (angular latitude of a star from the celestial equator) without explanation, and provides information that would mean little to many readers; a good example being: “RA 1 hr., 24 min (co-ordinates in -47.7 epoch)” (p. 105). The Glossary on pp. 47-8 is woefully short, with only ten entries, and the terms included get too brief a treatment. Since R. is a historian, the assumption is that the book is aimed primarily at other historians, but the astronomical jargon sometimes obscures the argument. R.’s engagement with other astronomical phenomena can also be superficial, such as his discussion of Posidonius’ eclipse comet, wherein he dismisses several solar eclipses because they are annular, without providing numbers for his readers to judge for themselves whether their magnitudes might make them candidates for the eclipse in question (pp. 90-1).
A further problem with the book lies in its formatting, which I found to be a hindrance at times. For example, the comet entries in the catalogue are each separated only by a bold heading, which is not sufficiently distinctive, and the heading for each comet with the pertinent information in it, while intended to give all the useful information at a glance, is untidy, with an irregular structure: symbols on the left, names for the comet in the centre, and varying cometary information on the right. The narrow width of the page renders this cluttered; a table, or other more regulated structure, might have been beneficial. Additionally, having the ancient texts at the end of the discussion is frustrating, and they would have been better at the beginning. While the tabular summary of comets on pp. 29-46 is a useful resource, the formatting is inefficient. It is spread across both pages of the open book, the columns are inappropriately sized for the entries: the column which contains only a tick for whether there is non-European sources for a comet is as wide as the one detailing other possible dates for it; similarly, the column for the record number is excessively large. This may have been better suited to a landscape format, with more efficient use of tables, or even a pull-out at the end of the volume. These problems in no way detract from the overall usefulness of the book. There are several, minor typographical errors within the volume, but I will not list them here.
I would recommend this book as a first port of call to anyone looking at comets in an ancient source. It gives clear, concise information regarding 73 objects in our sources that are, or have been thought to be, comets, a good bibliography, access to the evidence (including images of the numismatic evidence) and in many cases, a more precise and accurate re-dating of the comet. If it falls down in places because of the presentation format, and the lack of a general index, then this is more than made up for by the meticulous cross-referencing and the more general arguments that run as themes through the relevant examples.
Notes
1. Pingré, A. G. (1783), Cométographie ou Traité Historique et Théorique des Comètes. Vol. 1 (Paris); Gundel, W. (1921) ‘Kometen’ RE vol. 11.1, 1143-93 (Stuttgart); Barrett, A. A. (1978) “Observations of Comets in Greek and Roman Sources before A.D. 410.” Journal of the Royal Astronomical Society of Canada 72.81-106; Yeomans, D. (1991) Comets: A Chronological History of Observation, Science, Myth and Folklore. (New York); Kronk, G. (1999) Cometography: A Catalog of Comets. Vol. 1: Ancient to 1799. (Cambridge).
2. Schove, J. D. & Fletcher, A. (1984). Chronology of Eclipses and Comets: AD 1-1000. (Woodbridge, Suffolk). R. does not appear to have consulted this work while researching his catalogue, but this is not a significant omission as Schove & Fletcher only list the comets from AD 1 onwards, and provide neither sources nor discussion to accompany them.