Babylonian and Seleucid Dates

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This page gives access to two conversion tables in Excel format (905 kB), with a copy in HTML format (2.57 MB), useful for determining the Julian equivalent of Babylonian and Seleucid civil dates in the Ptolemaic era. The dates of some important events early in the Ptolemaic era, such as the death of Alexander, and of a number of Seleucid events involving Ptolemaic princesses, can be determined from these tables.

Three tables are provided:

1) The standard conversion table generated by Parker & Dubberstein in 1956 (PD)
2) A corrected conversion table, consisting of PD overlaid by data from contemporary astronomical diaries, lunar tables, eclipse reports, eclipse predictions, goal year texts and horoscopes.
3) A difference table, showing the differences between the first two tables.

The second of these tables is also provided in a CSV text format.

How to Read the Tables

The tables cover the period from 331 to 29 B.C. They open in a new window.

Month Entries

Each row entry in the main part of the first two tables give the Julian date for the daylight portion of the first day of the corresponding Babylonia or Seleucid civil month in the corresponding Julian or Seleucid year. Since the Babylonian day started at sunset, the actual start of the Babylonian day was the evening of the previous Julian day.

Month names are given across the top.

It should be noted that the correspondence of Macedonian month names to Babylonian ones were changed, at least in areas under Parthian rule, from some time before 48/7 B.C., until some time in the middle of the first century A.D. The Macedonian names as used in Parthian Babylon are recorded on the last line of the table, and the years to which they are known to apply, possibly alongside the standard equivalence, are given in blue. In one case a Macedonian intercalary month is attested (on coinage). This month is given in blue.

The problems of the alignment of the Macedonian calendar to the Babylonian are discussed here.

The following colour conventions apply to monthly entries in both conversion tables:

The following additional colour conventions apply only to monthly entries in the corrected table:

Year Entries

The left hand column gives the Julian year B.C. in which the corresponding Babylonian year starts. This is the Julian year most closely corresponding to the Babylonian year. The right hand column gives the Julian year B.C. in which the corresponding Babylonian year ends; this is the Julian year most closely corresponding to the Macedonian year. Every twentieth Julian year is bolded to assist in scanning the table. Every 19th year, starting from the death of Alexander (323/2) is italicised; this represents a complete additional cycle of 235 months since that date.

The second column on both the left and right hand side of the table normally gives the year number of the Seleucid Era (SE). The left hand side (in black) gives the Babylonian year number (SEB); the right hand side (in blue) gives the Macedonian regnal year number (SEM). It is generally believed, though on veyr little evidence, that the Macedonian year aways started in the Tashritu of the preceding Babylonian year. Thus the months from Nisanu to Tashritu have the same year number in both systems, but between Tashritu and Nisanu the Macedonian year number was one ahead of the Babylonian year number.

Note that there is no assumed correlation between the language of a month name and the year numbering system. For example, Tashritu in year 100 SE might be the seventh month of the Babylonian year (i.e. 12 Oct. - 10 Nov. 212) or the first month of the Macedonian year (i.e. 23 Sept. - 22 Oct. 213). This ambiguity can only be resolved by context.

The Seleucid era was inaugurated in 7 SEB = 305/4, retroactive to 1 SEB = 311/0. The first few years, in which the era is notional, are shown in parentheses. Earlier years were dated according to the regnal years of the individual Babylonian kings, which are shown in the third column in red. The names of the applicable kings -- Philip III and Alexander IV -- are given against the applicable years, which are shown in the third column of the table. The actual situation in these years is quite complex, and has only been fully resolved with the recent publication of the "Solar Saros" Table (BM 36754 = LBAT *1430) -- see T. Boiy, JCS 52 (2000) 115:

Finally, the Arsacid Era was used alongside the Seleucid Era after the conquest of Babylon by the Parthians in 141 = SE 171B = AE 107 (AD141, see R. J. van der Spek, AfO 44/5 (1997/8) 167, 171). The Arsacid Era starts in 247, with the successful revolt of Parthia against the Seleucid Empire. Arsacid Era year numbers are given in the third column in blue.

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