Sogdian, Choresmian, and Armenian calendarsOther ancient calendars that were structurally similar to the Egyptian calen-
dar, and more particularly to the Persian Zoroastrian calendar, are also most
likely to have been adopted in the Achaemenid period. The calendars of
Sogdiana, Choresmia (both in Transoxania, present-day Uzbekistan), and
Armenia are known from early medieval sources to have been identical with
each other; they were also identical, in the early Middle Ages, with the Persian
Zoroastrian calendar, but with some minor differences.^40 This identity of
calendars is remarkable, considering the vast geographical distance that lies
between Transoxania (south-east of the Aral Sea) and Armenia (west of the
Caspian Sea), and the fact that these regions are not known to have ever been
related either politically, commercially, or culturally. It seems most unlikely,
therefore, that this calendar was transmitted directly from Transoxania to
Armenia (or vice versa).We must assume, instead, that it was disseminated to
both regions from a common source, which can only have been Persia (de
Blois 1996).
However by the early Middle Ages, the Persian Zoroastrian calendar
differed slightly from that of Sogdiana, Choresmia, and Armenia. These
differences are significant and need to be explained. Firstly, in the Sogdian-
Choresmian-Armenian calendar, the New Year occurredfive days later than
in the Persian, i.e. on the 6th day of Persian Farwardīn; and secondly, the
epagomenal days were positioned at the end of the twelfth month, whereas in
the Persian Zoroastrian calendar they were positioned, rather oddly, at the end
of the eighth month (Ābān). Both differences are clearly related. It would seem
that originally all four calendars were identical, with—as in the Egyptian
calendar—the epagomenal days at the end of the twelfth month (their twelfth
month, however, corresponding to the Egyptian third month). Then, at some
stage, the Persians postponed their epagomenal days from the end of the
twelfth month to the subsequent eighth month, with the effect of bringing
their New Year forward byfive days.^41 Why they did so is unknown, but de
Blois (1996) makes a plausible suggestion. The intention may have been to
(^40) See Panaino (1990) 664–6; these differences will be considered in detail below. Evidence of
the Sogdian and Choresmian calendars derives entirely from al-Biruni (c.1000CE); his account
can be treated as reliable for his own period, not least because he was himself a native of
Choresmia, and also because the names of months he provides are largely corroborated by
ancient Sogdian and Choresmian sources (de Blois 1996: 46). Al-Biruni does not appear to have
known the Armenian calendar, but this calendar is well attested in late antique and early
medieval Armenian literature; for a summary, see Tumanian (1974), Panaino (1990) 664. Before
the introduction of the Persian Zoroastrian calendar, the calendar of Armenia is assumed to have
been lunar, as everywhere else in the Near East (Tumanian 1974); the evidence, however, is slim.
(^41) This scenario is far more likely than the reverse, i.e. that the epagomenals were originally at
the end of the eighth month, and that the Sogdians, Choresmians, and Armenians—by some
inexplicable common agreement—brought them forward to the previous twelfth month.
TheRise of the Fixed Calendars 179