throughout the vast expanses of the newly formed Achaemenid Empire.
A similar argument has been suggested above with regard to the regularization
of the Babylonian month and the use of advance predictions for the determi-
nation of month-lengths (}1); but with regard to intercalation the administra-
tive advantages of calendar regularization are even more evident. Once afixed
scheme or cycle became established and known, imperial administrators in the
more remote regions of the empire could easily calculate and predict when the
next intercalation was due. In this way, the whole empire was able to reckon
the same, identical calendar without depending on the sporadic and delayed
dissemination of calendrical information from the centre of the empire to its
periphery.
This policy appears to have achieved a measure of success. It is no coinci-
dence, indeed, that cases of inconsistency (i.e. where different cuneiform
sources assume different intercalated years) are confined to the early period,
largely the sixth centuryBCE.^134 Whilst we are unable to explain these incon-
sistencies,^135 it is significant that they hardly occur after the reign of Darius I,
oncefixed cycles of intercalations were introduced. Clearly, these cycles
enabled the same intercalations to be assumed in all cuneiform texts, without
any further inconsistencies.
The regularization of intercalation had also other imperial, administrative
advantages. Control of the calendar had always been a privilege of the king,
but in the context of the Achaemenid Empire, where the king was no longer
based in the city of Babylon or in Mesopotamia (except for limited periods of
time), management of the calendar of Babylon may have become a burden.
Again, the scale of the empire meant that it was no longer practical for kings to
participate in Babylonian calendrical decisions on a monthly basis. By insti-
tuting various intercalation schemes at the beginning of their reigns, Achae-
menid kings were able to assert their personal authority over the calendar
whilst not having to involve themselves excessively in matters of calendar
control. They could also maintain their authority over the calendar by
(^134) Inconsistencies occur in 596/5, 584/3, 597/8, 555/4, and 522/1 (thefirst year of Darius I),
as noted above in the tables. Two further cases occur in 509/8 and 506/5, but these are probably
errors. In the subsequent period, only one inconsistency occurs in 385/4 (as explained above,
most probably a reflection of the theoretical nature of the Saros Canon) and another in 267/6
(the only comparable case to those of the 6th c.).
(^135) Our information about the provenance of the cuneiform sources, for instance, is insuffi-
cient to establish whether these inconsistencies might have been due to regional difference and
the difficulty of communicating calendrical decisions to from one region to the next, as is attested
in the Elephantine papyri of the 5th c. In general, however, the provenance of our 6th-c.
cuneiform sources appears to be Babylonia; this does not readily account for these inconsisten-
cies, since the distance between various Babylonian cities was relatively small. In all the cases
from 596/5 to 522/1, the single inconsistent source places the intercalation one yearearlier(in
584/3, six months earlier; whereas in 509/8 and 506/5, the inconsistent intercalation is one year
later). This may well be significant, although I am unable to explain how.
122 Calendars in Antiquity