Why celestial omens appear first in Old Babylonian sources may be a consequence
only of selective survival of our sources. Brown ( 2000 : 151 ) showed, however, that
the vast majority of cuneiform celestial omina can all be reduced to a simple
prognostication of good or bad, accompanied by a statement as to which of four
countries the prediction applied to. Clearly, such a simple code would have been well
suited to an oral environment. Perhaps celestial divination was simply not written
down in the third millennium, but was deemed to be of sufficient importance that
it came to be included in the rich scribal repertoire of the Old Babylonian period,
resulting in its elaborate embellishment. Certainly, later generations of scribes assigned
third-millennium roots to celestial divination.^7
Although, as yet, evidence for the creation of a major series of celestial omens in
the Old Babylonian period is wanting, a proto-form of the compilation known by
its incipit (in Akkadian) as Enu ̄ ma Anu Ellil‘When the gods Anu and Ellil’ appears
to have existed then.^8 This omen series was seemingly redacted into a fairly stable
form during the Middle Babylonian period (c. 1200 BC), in common with many other
compositions, but is best known to us through many copies dating to the late Neo-
Assyrian period (c. 700 BC) and thereafter, when it was regarded as a composition of
divine authorship. Although wider in extent, there is little to distinguish the later
c. 70 -tablet Enu ̄ ma Anu Ellilfrom its Old Babylonian forerunner in terms of the
underlying principles used to determine prognostications from the heavens.^9
One tablet included among the 5 , 000 or so omens that make up the classical
version of Enu ̄ ma Anu Ellildeserves special mention. Tablet 1410 offers arithmetic
schemes (in one case with a geometric appendage) pertaining to the duration of lunar
visibility and the length of the night. They are of Old Babylonian origin or earlier
(Brown 2000 : 114 ; Brown and Zólyomi 2001 ). Although at first glance ‘astronomical’,
the schemes are in fact numerical elaborations based on a set of very simple assump-
tions, namely that the year lasts 360 days, that the longest night is twice the length
of the shortest, that months are 30 days long, and that mid-month occurs on the
fifteenth, during which time the Moon is visible from sunset to sunrise, and finally
that change is linear. These numerical elaborations mirror the word-based elaborations
that formed the celestial omens. The assumptions made, however, do not permit one
to predict, even remotely accurately,^11 the length of lunar visibility on any given
day. What, then, was the purpose of such schemes? Brown ( 2000 : § 3. 1 .2)argued
that the numerical elaborations described the ideal behaviour of the universe and its
constituents. The assumptions behind tablet 14 correspond exactly to the parameters
of the year and month as laid down by Marduk when he formed the universe according
to the Epic of CreationV i f. (Brown 2000 : 235 ), for example. When the universe
was seen to run according to the pattern of its ideal, original construction, that boded
well, when not, it boded ill. For example, 30 -day months boded well, whereas months
of any other length boded ill. Many other examples are adduced (Brown 2000 :
146 – 51). Far from being an early attempt to calculate the phenomena of the heavens
beforehand, tablet 14 offered a way of permitting the diviner to make interpretations
on any day of the year, by comparing the length of observed lunar visibility with
the ideal value.
Tablet 14 of Enu ̄ ma Anu Ellilis ‘astrological’ in purpose, and its placement within
a series of omens is entirely appropriate. The two-tablet series known by its incipit
as Mul.Apin ‘the Plough Star’ (this is not Ursa Maior, incidentally) outlines many
— Mesopotamian astral science —