4
The Rise of the Fixed Calendars: Persian,
Ptolemaic, and Julian Calendars
Before the sixth centuryBCE, nearly all the calendars of the Mediterranean and
the Near East wereflexible, variable, and under the control of political rulers;
but in the course of the following centuries these calendars evolved, in
different ways, intofixed and immutable schemes. This remarkable change
began in late sixth- or earlyfifth-century Persia, with the institution of the
Persian Zoroastrian calendar, and culminated in 46BCEin Rome, with the
institution of the Julian calendar. Other calendars were also affected, though to
a lesser degree: thus the Babylonian calendar, with the adoption in this period
offixed 19-year cycles (see Chapter 2), and to a lesser degree still, the slow
regularization of the calendars of Greece (Chapter 1) and of pre-Julian,
Republican Rome (below in this chapter).^1 By the end of thefirst millennium
BCE, however, the majority of ancient calendars had becomefixed. This had
long-term historical consequences. The Julian calendar, as is well known, went
on to establish itself as dominant in the Roman Empire, in late antique and
medieval Christendom, and much later (in its slightly modified, Gregorian
form) throughout the modern world. This chapter is thus not simply about the
rise and development of a few ancientfixed calendars, but about a major
process which affected the whole of the ancient world and eventually led to the
formation of our modern calendar today.
The most decisive factor, in this general shift fromflexible tofixed calen-
dars, was the spread and influence of the Egyptian calendar. During the last
centuries of thefirst millenniumBCE, the Egyptian calendar—the onlyfixed
calendar to have existed in earlier Antiquity—began spreading to a number of
regions, some astonishingly remote. This occurred, however, in very different
(^1) For an excellent study of the progressive centralization and standardization of the Roman
calendar in the Republican and early Imperial periods, mainly from the perspective of the
calendar’s contents (i.e. annual festivals and qualified days), see Rüpke (1995). In this chapter,
as elsewhere in this book, I focus only on the bare structure of the calendar, i.e. how months and
years were reckoned.