ButCaesar himself was no scientist (in spite of some attempts to project such an
image of him); he was driven by politicalmotivations, not by the progress of
astronomy. The rabbinic calculation of themolad(conjunction or‘new moon’)
was perhaps the closest attempt in history, in the context of afixedlunar
calendar, to track thelunar month on the basis of accurate, state-of-the-art
astronomicalvalues. This was achieved by avoiding the use of schematic cy-
cles—at the expense of arithmetic neatness and practicalconvenience—and
adopting instead a complex calculation drawn from astronomicalsources, prob-
ablyPtolemy’sAlmagest(Stern 200 1 :200– 1 0).However, this earlymedieval
calendar scheme (first attested in the eighth century)lies outside the period and
scope of this study.
Besides astronomy, whichIam arguing had alimited impact on the history
of ancient calendars, consideration must be given to the arithmetic skills that
were employed in the design offixed, schematic calendars. There is a good case
for arguing, indeed, that the development of such calendars inlater Antiquity
was facilitated by progress in arithmetic techniques. Thefixed,lunar calendar
schemes that were designed in various parts of the ancient world from the
Hellenistic period (third centuryBCE) untillate Antiquity were particularly
sophisticated, as in most cases they were synchronized with other, solar (or
nearlysolar) calendars: these include the Greek astronomicalcalendars, the
lunar cycles fromPtolemaic Egypt, the Qumran calendar rosters, and inlate
Antiquity, theChristian Easter cycles. The arithmetic ingenuity of these
calendar schemes, especially the Qumran calendars and the Easter cycles,
reflects a certainlevelof technicalor scientific progress which warrants the
inclusion of these calendars in the history of science in Antiquity.^18
This said, progress in arithmetical techniques—just like progress in
astronomy—cannot explain, on its own, how and why ancient calendars
arose and developed the way they did. The design of Qumran calendars and
Christian Easter cycles was religiously motivated andlargely determined by
religious traditions; whilst in most other ancient calendars politicalfactors
played an essentialrole. For reasons explained above, indeed, most ancient
calendars were instituted and controlled by politicalrulers, and their develop-
ment—even in the case of the Julian calendar, despite its explicit astronomical
foundations—was driven by politicalmotivations. To treat ancient calendars
(^18) e.g. Neugebauer ( 1975 ). Qumran and Easter calendars oftenlacked astronomicalsophisti-
cation, being constructed on the basis offixedlunar and solar values that were borrowed from
other sources and whose astronomicalmeaning was not necessarilyfully understood; but it is
important to note that schematic calendars (and especiallycalendar cycles) tend by nature to
favour arithmeticalneatness over astronomicalaccuracy. On the relationship between astro-
nomicalscience and these schematic calendars, see, on Qumran, Glessmer ( 1996 a) and Ben-Dov
(2008), and on Easter cycles, McCluskey ( 1 998), McCarthy and Breen (2003), and Lejbowicz
(2006).
14 Calendars in Antiquity