Babylonian and Seleucid Dates
Intro page | How to Read the Tables | The Babylonian Calendar | Sources | Analysis
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.
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.
The first row gives the Babylonian month names bolded in black.
- The second row gives the corresponding Macedonian month names in the Seleucid calendar, bolded in blue.
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 Babylonian civil month in which an Egyptian civil year begins is shaded in green.
- The Babylonian civil month in which a Julian year begins is shaded in yellow.
- The Babylonian civil month in which a Julian leap day (i.e. 29 February) is intercalated is shaded in light blue.
- Macedonian month names and year boundaries, which are generally half a year out of phase with the Babylonian year, are given in blue.
The following additional colour conventions apply only to monthly entries in the corrected table:
If the length of the previous Babylonian month is known from lunar tables only, the start date is given in green.
- If the length of the previous Babylonian month is known from astronomical diaries or horoscopes, the start is given in red, even if it is also known from lunar tables (i.e. lunar tables are assumed to be derived data, while the diaries and horoscopes are assumed to be primary sources).
- If the length of the previous Babylonian civil month is given conflicting values in two or more Babylonian sources, the selected start date is given in magenta; these cases are discussed here.
- If a month is the first month of an unbroken sequence of months, the start date is given in brown.
- If the start date of a month can be determined from astronomical data other than eclipses, it is underlined, and usually in red, unless there is a data conflict. All such months are taken from Table 1 of L. J. Fatoohi et al., JHA 30 (1999) 51, and Tables 1 and 2 of S. Stern, JHA 39 (2008) 1, which lists them because they contain observations or predictions of first lunar visibility which can be converted to Julian dates. There are probably others.
- If the start date of a month can be determined absolutely from an observed solar or lunar eclipse, the date of the start of the month is given in red; such dates have colour precedence over all others
- If the start date of a month can be determined absolutely from a predicted solar or lunar eclipse, the date of the start of the month is given in red; such dates have colour precedence over all others except observed eclipses.
- If there is a calendrical synchronism between the Babylonian calendar and another calendar, the date of the start of the month is given in purple. There are only four such synchronisms, three to the Egyptian calendar (from the Almagest) and one to the unsubordinated Macedonian calendar (the date of death of Alexander the Great).
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:
Philip III acceded in year 1 = 323/2 on the death of Alexander the Great, and died in his year 7 = 317/6. However, his death was not immediately known in Babylon, so dating continued well in to his year 8 = 316/5.
Alexander IV acceded in year 1 = 316/5 and remained nominally king until year 11 = 306/5, although he was actually murdered in year 7 = 310/9. While dates are known from Babylon his years 1 and 2, we also have an later table of eclipse possibilities stating that year 7 of Philip III was followed by year 2 of Antigonus.
Antigonus Monophthalmus operated his own regnal years as viceroy of Asia (strategos and satrap -- "rab uqu" -- in Babylonia) from the death of Philip III, in his year 1 = 317/6, until his year 6 = 312/1, instead of the years of Alexander IV, although he was never recognised as king. However, the first year recognised by later kinglists was his year 3 = 315/4, following on year 8 = 316/5 of Philip III, so his regnal years are probably antedated. Dates are also known from years 8 = 310/09 and 9 = 309/8, when he was contending with Seleucus for control of Babylonia.
From Alexander IV year 6 = 311/0, Seleucus was recognised as strategos. This event was the basis of the Seleucid Era, but (as noted above) he did not start using it until he assumed the title of king in 7 SEB = 305/4. Before then he used the years of Alexander IV. While his reign is generally accounted by years SEB, the true chronolog is occasionally noted, e.g. in GYT 5 = LBAT *1216+*1217 = BM 32154+32408 notes an observation of Jupiter in year 10 (SEB) = year 4 of king Seleucus (I).
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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