and administratively more expedient, to use Macedonian month-names for
Babylonian months and thus to assimilate the former to the latter.
There are several reasons why it is the Macedonian calendar that was
assimilated to the Babylonian, and not vice versa. Although the Babylonian
calendar had always been under royal control, which might have given the
right to Seleucid rulers to modify it in line with a Macedonian calendar, they
may have been reluctant to interfere with a calendar that was well regulated by
astrologers in the great Babylonian temples. As we have seen in Chapter 2, it is
under the Seleucids that the Babylonian cycle of intercalations becamefirmly
fixed, perhaps because Seleucid kings did not consider themselves sufficiently
‘Babylonian’to tamper with the Babylonian calendar or to dictate how it
should be reckoned.
The Macedonian calendar was also more suited to becoming adapted to the
Babylonian calendar (rather than vice versa) because of its inherentflexibility.
Little is known about the original, pre-Seleucid Macedonian calendar, but as a
Greek lunar calendar, it is likely to have allowed the arbitrary intercalation and
suppression of days, and the intercalation of any month of the year (see
Chapter 3, near n. 89). In the Babylonian calendar, in contrast, all months
began regularly at the new moon, and only a second month of Ululu (VI 2 )or
Addaru (XII 2 ) could be intercalated (see Chapter 2). The Macedonian calen-
dar could therefore become adapted to the Babylonian without its identity’s
being compromised, whereas the reverse would not have been so easy. The use
of Macedonian month-names made it possible for the Seleucid calendar to be
still construed as‘Macedonian’, even though it had adopted the rigid structure
of the Babylonian calendar.
The evidence we have surveyed, however, suggests only the assimilation of
Macedonian month-names to Babylonian months, and hence (implicitly) the
adaptation of the Macedonian calendar to the Babylonian 19-year cycle of
intercalations; but it is far from certain that calendar assimilation went any
further, e.g. with months in both calendars beginning exactly on the same
days. It must be remembered, as has been stressed in previous chapters, that it
was generally impossible to maintain an identical lunar calendar across the
vast imperial territory of the Seleucids. Although Babylonian intercalations
were standardized andfixed by the Seleucid period, which made it possible for
the same intercalations to be carried out throughout the Empire, the beginning
of the months did not conform to anyfixed cycle or pattern, but depended
instead on a sophisticated combination of empirical new moon sightings and
astronomical predictions of itfirst visibility that were carried out by astrol-
ogers in the great temples of Babylonia (see Chapter 2). Anyone at a distance
from Babylonia and without the benefit of Babylonian astronomical expertise
would have been incapable of knowing or predicting when exactly the Baby-
lonian month had begun. Already in the Achaemenid period, this had led to
someflexibility and diversity with how the Babylonian calendar was reckoned
242 Calendars in Antiquity