67 – 8), not only in documents written at the end of the month, but also in
documents written earlier in the month and anticipating its end.^54
If, as I am arguing, day-30 dates were regularly used in administrative/
economic documents on a purely provisional or tentative basis, the informa-
tion they give about the Babylonian calendar can only be very limited. They do
not indicate which months, in the calendar, were eventually determined to be
of 30 days. In some contexts, for example if a document was written later and
retrospectively dated, the day-30 date could be treated as informative about
the calendar. But to identify such cases would require a detailed, qualitative
analysis of the sources which Huber did not undertake. His sample of admin-
istrative/economic sources needs, in any event, a thorough re-examination.
My suspicion is that if provisional and tentative day-30 dates could be
successfully weeded out, the remaining sample of 30-day months would be
as astronomically accurate as the months attested in the Astronomical Diaries.
But until such a re-examination is carried out, it is safer to leave administra-
tive/economic sources aside and restrict ourselves to the evidence of astro-
nomical sources.
As an appendix to our discussion of 30-day months, mention should be
made of the 360-day year scheme, although it is unlikely to explain the high
incidence of 30-day months in Huber’s sample. This scheme, consisting of
twelve months of 30 days, originated in Mesopotamia in an administrative
context: during the second half of the third millenniumBCE, it was in standard
use for the calculation of accounts over lengthy time periods.^55 Its purpose was
only to simplify accounting, not to serve as an annual calendar; the calendar
that was used for dating and other general purposes was lunar.^56 Although the
360-day scheme was inaccurate in relation to the real-life lunar calendar
(where months could be 29 or 30 days long), it was acceptable as an adminis-
trative convention because it could work equally for or against the interests of
the state’s bookkeepers (Englund 1988: 129–30). It fell into disuse as an
administrative scheme in the second millenniumBCE, but was then taken
(^54) e.g.YBT7. 123 (English translation in Fried 2004: 40) is dated 25 Arah
:samnu (528BCE) and
refers in advance to‘30 Arah:samnu’(other documents sometimes refer neutrally to the‘end of
month’). This assumption is also made in astrological texts, where one-month periods are
referred to as 55 ‘from day 1 to day 30’(e.g. Hunger 1992: nos. 4–5).
Englund (1988) 122–33, Brack-Bernsen (2007). This scheme was used to calculate salaries,
allowances, rent, expenses, goods to be delivered, etc. over extended periods. In an intercalated
year, the year-length of 390 days was assumed (thirteen 30-day months).
(^56) As Brack-Bernsen (2007) emphasizes, the 360-day scheme is never used as a dating method
in the sources. Neugebauer (1942) 400–1 describes the 360-day year as afixed, schematic
calendar, which would have been used by administrators and businessmen for the purpose of
determining future dates‘regardless of the irregularities of the moon and the inability of the
astronomers to predict the outcome’. But this interpretation is not supported by the evidence,
and only reflects a modern, anachronistic concern for calendar regularity and predictability
which the lunar calendar did not offer.
The Babylonian Calendar 87