The institution of afixed cycle: the evidenceIt is commonly accepted that in the Achaemenid period, from the earlyfifth
centuryBCE, the intercalation wasfixed through the adoption of a 19-year cycle
(comprising seven intercalations). Thisfixed cycle meant, effectively, that the
king and astrologers lost their authority to determine intercalations at will. If
this accepted notion is correct, its socio-political implications would thus be
quite considerable.
The institution of afixed cycle is not explicitly referred to in any source, but
can be inferred from sequences of known intercalated years. Intercalated years
are sporadically attested for the Assyrian and early neo-Babylonian periods,^99
but almost completely and continuously from the late seventh to early second
centuriesBCE. It is through analysis of this continuous sequence of intercala-
tions that modern scholars have inferred the existence of afixed, 19-year cycle
from the beginning of thefifth centuryBCE.^100
This consensus can be criticized, however, from two opposite directions. On
the one hand, the 19-year cycle was not consistently reckoned in the Achae-
menid period, and I shall therefore argue that it took some time for the 19-year
cycle to become fullyfixed. On the other hand, I shall argue that the process of
fixing intercalation was already initiated under Cyrus, at the beginning of the
Achaemenid period, and that some earlier attempts were even made in the
early neo-Babylonian period. Thus thefixed cycle was not a sudden institution
of the earlyfifth century; it was the result of a gradual process which began
early and was not completed until late in the Achaemenid period. Neverthe-
less, the turning-point was clearly the beginning of Achaemenid rule.
My analysis of the origins and development of intercalation cycles will be
based on ChristopherWalker’s (unpublished) list of intercalated years with
the cuneiform sources that attest them.^101 I have supplemented this list on the
basis of texts published in Sachs and Hunger (1988–2006) and Hunger (1988),
(1999) (the latter only for the Seleucid period). For reasons of scope, I shall not
provide references to the cuneiform texts attesting every intercalated year (as
inWalker’s list), except only in controversial cases.
(^99) For the years 684–51, see Parpola (1970–83) ii. 381–2; many of his entries, however, are
unsubstantiated and only based on a presupposed‘intercalation pattern’. For the reign of
Kandalanu (646–628), seeWalker (1999). My approach, followingWalker (as explained
below), is empiricist and minimalist in comparison to Britton (2007) 120–3, who claims that
from 667BCEonwards the record of intercalations is‘nearly complete’.
(^100) See mainly Parker and Dubberstein (1956), Aaboeet al.(1991) 14–16, and Britton (1993)
66 – 8, (2007) 120–3. See alsoWacholder andWeisberg (1971) 234–7, Hartner (1979) 2–3 and
(1985) 742–3, Bowen and Goldstein (1988) 42 n. 17, Britton andWalker (1996) 46, 52, Brown
(2000) 261, Assar (2003) 174.
(^101) I am grateful to ChristopherWalker for his generous assistance, and in particular, for
giving me a copy of this provisional list.
The Babylonian Calendar 99