This assumption is based on the premise that diversity of calendars cannot
be sustained within a single, undivided society. Indeed, the main purpose of
calendars is to time and coordinate human events and activities; a shared
calendar is therefore essential to social life and social cohesion. If every
individual were to reckon a different calendar, coordination would become
impossible and the whole purpose of the calendars would be defeated. Calen-
dars must therefore generate consensus, and be themselves consensus. As we
have seen throughout this study, calendar consensus was effectively estab-
lished through political authority: most calendars were controlled by political
rulers, and constituted therefore a political function and political privilege.
Even in the rare, perhaps imaginary cases where the calendar was not deter-
mined by political authorities but left instead to the individual to decide, such
as at Abdera and Ceos, the assumption tends to be that somehow or other—
though exactly how remains a little mysterious—a consensus eventually must
have emerged (see Chapter 1. 1). Conversely, and following this line of
argument, deviation from the calendar consensus, and indeed any form of
calendar divergence, must inevitably have led to social division and schism.
This is because the adoption of a different calendar inevitably disrupts the
proper synchronization of human events and activities, which in turn disrupts
the social order and causes it to split. On this basis it has been argued that
calendar divergence generated internal division within religious groups, and
led in particular to the formation of‘sects’and‘heresies’.
The question, however, is whether calendar consensus is really essential to a
properly functioning society, and whether calendar divergence—just as any
other form of social and cultural diversity—is necessarily a threat to social
cohesion. As we have seen in the previous chapters, calendar diversity often
accompanied geopolitical fragmentation and sociopolitical dissidence; but it
could also be accommodated, simultaneously, within diverse but undivided
societies. There is no evidence, for example, that the Gallic calendar of Coligny
or the use of lunar dates in Imperial Roman-period Italian inscriptions—in
conjunction, significantly, with Julian dates—led in any way to social division
or schisms. This is because society tolerates, by necessity, a certain extent of
diversity between its individuals (or subgroups of individuals); diversity is only
a threat to social cohesion if it is perceived to transgress acceptable limits. As
has been recently argued (King 2008), late antique heresiological discourse
and the identification of certain Christian groups as ‘heretical’depended
entirely on an implicit, ever-shifting, and constantly renegotiated definition
of what diversities within Christianity could be considered tolerable—and
therefore not‘heretical’—and what could not. The critical question, therefore,
which will be raised in this chapter, is whether or to what extent ancient
society was able to tolerate internal calendar divergence, and to what extent
calendar divergence was treated in society as a significant issue.
358 Calendars in Antiquity