ificant name
E-ur-imin-an-ki,[1333] _i.e._, 'the house of the seven directions of
heaven and earth.' The 'seven directions' were interpreted by the
Babylonian theologians as a reference to the seven great celestial
bodies,--the sun and moon and the five planets Ishtar, Marduk, Ninib,
Nergal, and Nabu.[1334] To each of these gods one story was supposed to
be dedicated, and the tower thus became a cosmological symbol,
elaborating in theological fashion the fundamental idea of the zikkurat
as a reproduction of the dwelling-place of the gods. The identification
of the five gods with the planets is a proof of the scholastic character
of the interpretation, and hence of its comparatively late origin. This
interpretation of the number seven, however, was not the only one
proposed in the Babylonian schools. Two much older towers than those of
Babylon and Borsippa bear names in which 'seven' is introduced. One of
these is the zikkurat to Nin-girsu at Lagash, which Gudea[1335]
describes as 'the house of seven divisions of the world'; the other, the
tower at Uruk,[1336] which bore the name 'house of seven zones.' The
reference in both cases is, as Jensen has shown,[1337] to the seven
concentric zones into which the earth was divided by the Babylonians. It
is a conception that we encounter in India and Persia, and that survives
in the seven 'climates' into which the world was divided by Greek and
Arabic geographers. It seems clear that this interpretation of the
number seven is older than the one which identified each story with one
of the planets.[1338] Both interpretations have a scholastic aspect,
however, and the very fact that there are two interpretations, justifies
the suspicion that neither furnishes the _real_ explanation why the
number seven was chosen.

It by no means follows from the names borne by the zikkurats at Lagash
and Uruk that they actually consisted of seven stories. The 'seven
divisions' and the 'seven zones' are merely terms equivalent to
'universe.' The names given to the towers would have been equally
appropriate if they consisted--as they probably did--of fewer stories
than seven. But, on the other hand, the introduction of the number seven
into the names may be regarded as a factor which influenced ambitious
builders to make the number of stories seven. Over and above this,
however, seven was chosen, primarily, because it was a large number,
and, secondly, because it was a sacred number,--sacred in part