Syriac sources outside the Roman Empire, e.g. in the Syriac Martyr Acts, can
only be attributed to the spread of Christianity, a‘Roman’religion, into the
Sasanian east.
But in a significant number of cases, the Syrian dates in the Syriac Martyr
Acts refer to lunar calendars, sometimes explicitly designated in the sources as
‘according to the moon’. These dates are only used in relation to events that
took place outside the territory of the Roman Empire (i.e. in Persian Meso-
potamia and the adjoining regions) and clearly reflect local, Mesopotamian
calendrical traditions that were presumably still alive under Sasanian rule.
Elsewhere I have shown, however, that the calendars assumed by these lunar
dates were not necessarily the standard Babylonian calendar, but might in fact
conform to a variety of lunar calendrical schemes (Stern 2004). In the Syriac
Martyr Acts, some of the lunar dates conform to the standard Babylonian
scheme (on which see Chapter 2), with months beginning atfirst visibility of
the new moon and thefirst month (Nisan) beginning after the vernal equinox;
but in other cases, the lunar calendar seems to be based on principles similar to
the Christian Easter cycles (on which see Chapters 6–7), with months begin-
ning slightly earlier, at the conjunction, and thefirst month beginning fre-
quently before the equinox. The differences between these lunar dates and
calendars are likely to reflect the practices of the different localities where the
martyrdoms took place and where their dates were originally recorded.
As argued earlier in this chapter, some diversity between lunar calendars is
likely to have existed at all times, even when the Babylonian calendar was used
as official calendar under the earlier empires. However, when under the
Sasanians lunar calendars (Macedonian and Babylonian) ceased to be used
as centrally controlled, official imperial calendars, diversity between local
lunar calendars in Persian Mesopotamia is likely to have significantly
increased. As conformity to an imperial lunar calendar was no longer neces-
sary, cities and localities were free to adopt a variety of lunar calendar schemes.
This would explain the great disparity of lunar dates in the Syriac Martyr Acts.
In this context, Christian influence seems to have been an important factor
towards calendar diversification. Some Christian communities may have
deliberately abandoned the Babylonian calendar, based as it was on the
empirical sighting of the new moon, and adopted instead a fixed lunar
scheme similar to or identical with the Christian Easter cycles.^176 Others
may have adapted to the Christian Easter cycles in a milder form: they may
have still sighted the new moon but reckoned the month of Nisan earlier in the
year, so as to make it coincide with the month of the Jewish Passover and
(^176) Thesefixed cycles, consisting normally of afixed alternation of 29- and 30-day months,
will be discussed in Chs. 6–7.
296 Calendars in Antiquity