further, and perhaps decisive, argument against the historicity of this claim,
intimated also by de Blois, is that if the Persian Zoroastrian calendar had been
intercalated prior to the Islamic period, the position of its New Year would be
inexplicable. Indeed, at the beginning of the Islamic period we know that the
Persian Zoroastrian year began around the summer solstice (from which point
it has been drifting, by one day every four years, until today). If prior to that it
had been regularly intercalated, and thus maintained in stable relation to the
seasons, its New Year would always have occurred in the season of the summer
solstice; yet this would run counter to the well-established, ancient Persian
Zoroastrian tradition of beginning the year at the vernal equinox.^31 It is
reasonable to assume that the Persian Zoroastrian calendar was originally
instituted in such a way that Farwardīn, thefirst month, occurred around the
vernal equinox; whereas a New Year around the summer solsticefinds no
justification in the context of Persian or Zoroastrian tradition.^32 If we assume,
however, that the Persian Zoroastrian calendar wasnotintercalated in the pre-
Islamic period, just as it was not intercalated later, the position of Farwardīn
can easily be explained. If at the beginning of the Islamic period Farwardīn was
at the summer solstice, then in the early Achaemenid period (c. earlyfifth
centuryBCE) it would have occurred in the spring, in accordance with the
traditional Persian New Year. At that time, the Egyptian New Year occurred in
the winter; the Persians, however, would have chosen the Egyptian fourth
month (IV Akhet or Choiak), then occurring in the spring, as Farwardīnor
first month of their own year—a correspondence that remained throughout
the history of both calendars.
This argument, that the Persian Zoroastrian calendar was never intercalated,
leads also to the conclusion that it was instituted in the early Achaemenid
month of Sapnadarmad (= Persian Isfandārmuä), on Friday, year 9 of Yazdgerd (447 CE)’. The
occurrence of 18 H:aziran in Isfandārmuäis only possible if we assume that the ancient Persian
Zoroastrian calendar was intercalated, and that the last intercalation was made after 447 CE, in
the reign of Peroz (459–84) (as reported by al-Biruni in one work, but contradictory to his report
elsewhere that the last intercalation was made in the reign of Yazdgerd I, i.e. in 399–420; see de
Blois 1996: 40). However, the weekday remains problematic, as 18 H:aziran (whether interpreted
as a Julian date, i.e. 18 June, or as a lunar date) should have been a Tuesday orWednesday, not a
Friday. It may be argued that‘Friday’, in this text, is only a literarytoposfor martyrdom dates.
However, it seems more plausible that‘H:aziran’in this text is an error for the next Syriac month,
Tammuz, when the 18th of the month would have been a Friday (whether a Julian or a lunar
date) and would have coincided with Isfandārmuäin a non-intercalated Persian Zoroastrian
calendar (as argued in Stern 2004: 462–3; the possibility of an intercalated calendar was over-
looked in this article, but it should still be regarded as less likely).
(^31) According to Boyce (1975–91: i. 175), this tradition was instituted by Zoroaster himself.
(^32) The position of Farwardīn around the summer solstice cannot be explained as having been
determined by the Egyptian calendar (on which the Persian Zoroastrian calendar was originally
modelled), because throughout the period when the Persian Zoroastrian calendar is likely to have
been instituted, i.e. from the Achaemenid conquest of Egypt to the reform of the Egyptian
calendar under Augustus (see below), the Egyptian New Year (1 Thoth) never occurred around
the summer solstice, only in the winter and the autumn.
176 Calendars in Antiquity