scheme was slightly more precise than the 2½-year scheme of Nabopolassar,
although it entailed, this time, slightly insufficient intercalation.^107
Alternatively, it is possible to identify in these years the institution of afixed
eight-year cycle. This cycle, known in later Hellenistic sources as the‘octae-
teris’, has three intercalations in years 3, 6, and 8. If we assume that it did not
matter which month (VI 2 or XII 2 ) was intercalated in these years, the cycle
could have started from year 8 in 533/2. In the second cycle, starting from year
8 in 525/4, the intercalated months were XII 2 , XII 2 , and VI 2 (in years 8, 3, and
6 respectively); this sequence was then repeated unchanged until about the end
of the century (see Table 2.2).^108
Table 2.2.Intercalations under Cyrus, Cambyses, and (early) Darius I
Year (BCE) Intercalation
(month number)
Interval from previous
intercalation (number of years)Year number
in 8-year cycle541/0 XII 2 ––
537/6 VI 2 3½ –
536/5 XII 2 1½ –
533/2 XII 2 38
530/29 VI 2 2½ 3
527/6 VI 2 36
525/4 XII 2 2½ 8
522/1a XII 2 33
519/8 VI 2 2½ 6
517/6 XII 2 2½ 8
514/3 XII 2 33
511/0 VI 2 2½ 6
509/8b XII 2 2½ 8
506/5c XII 2 33
503/2 VI 2 2½ 6
500/499 XII 2 3½ –
aThis intercalation is well attested. One text, however, has XII 2 in 523/2: BM 33066, in Strassmaier (1890) no.
- This is probably an error, but other explanations might be considered; for example, uncertainty or
confusion might have arisen in these years because of the succession crisis between the reigns of Cambyses
and Darius I.
bThis intercalation is well attested. One text, BM 65215, appears to place this intercalation one year later in
508/7 (Walker unpubl.), but this is probably an error.
cDitto, with only BM 55782 suggesting instead 505/4, probably an error.
(^107) With eight intercalations in 22 years, slightly less than the optimal seven in 19 years.
(^108) It is also possible to identify a repeated sequence of VI 2 , XII 2 , and XII 2 (in years 6, 8, and 3,
respectively) starting from 527/6, as other scholars have already suggested (Hartner 1979: 3,
1985: 742–4, following van derWaerden; Britton 1993: 67–8; Assar 2003: 174). These scholars
did not consider, as I am suggesting, that the eight-year cycle could have begun in 533/2 (still in
Cyrus’reign), because of an implicit assumption that in this cycle, the intercalary months cannot
be altered (and according to the post-527/6 sequence, the intercalary month in 530/29 should
The Babylonian Calendar 103