ROMAN - CHRONOLOGY Roman chronology was in antiquity wholly dependent upon Greek methods, and hence suffered from all the drawbacks of the latter (see CHRONOLOGY : Greek), together with a further one, viz., the scarcity and untrustworthiness of native documents. Working along the lines of the Alexandrians, several Roman scholars, not ably Varro and Atticus (the friend of Cicero) arrived at chrono logical schemes for the early history of Rome, whereof consider able fragments have come down to us in the various historians and antiquarians whose works survive, in lists of magistrates such as the fragmentary Fasti Capitolini,and in S. Jerome's chronicle. They are without exception highly untrustworthy for the regal period and the earlier centuries of the Republic (see ROME, History), but at least provide us with an epoch by which to reckon : that from the conventional date (753 B.C. of our reckoning) of the founda tion of Rome.
Founding of Rome.—Even this date was by no means a matter on which unanimity was reached; that given is the one which ultimately found most favour, and to which the majority of ancient authors refer when they use the expression a.u.c. (ab urbe condita, or anno urbis conditae). The official method of dating was by consuls, as M. Messalla et M. Pupio Pisone consulibus (abbreviated cos. or toss.), "in the consulship of Marcus Messalla and Marcus Pupius Piso" (Caesar, de bell. Gall., 1, 2, I (61 B.C.). This never quite went out of use; but under the empire, official documents emanating from the emperors or re ferring to them reckoned by their years of tribunician power, to which were frequently added other, less regularly recurring, dis tinctions, such as the consulate or the salutation as imperator, e.g., Imperator Caesar V espasianus Augustus ponti f ex maxima, tribuniciae potestatis imp(erator) xiix, consul viii, i.e., "Vespasian (name and titles in full), in the ninth year of his tribunician power, having been saluted imperator 18 times, con sul for the eighth time" (A.D. 77; from an official letter C.I.L., 11, 1423) . As, however, documents relating to the emperors are very numerous, this method of dating seldom raises much diffi culty; our list of consuls also, for the fully historical periods, is tolerably complete. Naturally, in dealing with pre-Caesarian years (see CALENDAR, Roman) calculations more or less elaborate are needed to convert the year urbis conditae into the conven tional Julian year (cf. CHRONOLOGY: Greek) . These are based on a few facts, such as the mention of an eclipse or other event which we can date accurately. One such eclipse was that of the sun on Oct. 19, 202 B.C. ; we gather from various authors that its civic date was about the beginning of December, and this enables us to calculate the condition of the calendar at that time.
More important for the determining of Roman imperial dates, than the former, and for some of the later Republican dates also, are the provincial eras and the indictions. It was a wide-spread custom in Hellenistic times to count years from some notable event. The accession of the reigning king was, and continued to be, commonly used, and this, as we have seen, was followed by the emperors; but the Seleucidae and their subjects counted from 312/11 B.C., the date of Seleucus Nicator's decisive victory at the battle of Gaza and his capture of Babylon. In like manner a few Roman chronologists counted from 46 B.C., the date of the Julian reform ; and Spain had an era of its own, beginning with 38 B.C., a date chosen for no very obvious reason. Again, several independent cities, such as Antioch, had local eras. When, there fore, we find a year mentioned in an inscription or other piece of evidence, it is necessary to know where this was written, and thus whether the Seleucid era, or that of Spain, or Antioch, or some other place, is meant ; or, if the author be a historian, whether he may be using some peculiar era of his own, counting, for example, from the date which he accepts for the fall of Troy, or from the death of Alexander the Great.
The indictions are late, but important for late events, for they appear in all manner of official documents, ecclesiastical and secular. Properly, indictio means an assessment of taxes; nec novis indictionibus pressi ad vetera tributa deficiunt, says the younger Pliny (Paneg. 29), "the provincials are not so ground down with fresh exactions as to be unable even to pay the old taxes." Under Diocletian, a five-yearly assessment was ordered, and three of these periods grouped together made what was now called an indiction. One authority traces this arrangement back to comparatively early times, making the first indiction begin in 49 B.C. ; but the real date seems to be A.D. 297, although even at the beginning of the empire the germ of such a system existed in Egypt. Its chronological importance is, that it provided a means of dating, without mentioning the several emperors who, by Diocletian's arrangement, ruled simultaneously. A disad vantage was that the cycle began on different days at different times and places. Despite these differences, and the fact that indictio meant now the whole cycle, now a year of it, it remained in use until the middle ages, and here and there even later. See CHRONOLOGY: Greek; CALENDAR: Greek ; CALENDAR: Roman; also Clinton, Fasti Romani, vol. i., 1845, vol. ii., 185o; Seeck, art. "Indictio," in Pauly-Wissowa, Realencyclopddie, and literature there cited. (H. J. R.)