According as the one or the other aspect of such a power is brought into the foreground, Ishtar becomes the mother of mankind, the fertile earth, the goddess of sexual love, and the creative force among animals, while at times she appears in hymns and myths as the general personification of nature.

We thus find in the post-Khammurabic period the pantheon assuming distinct shapes. The strong tendency towards concentrating in one deity - Marduk - the attributes of all others was offset by the natural desire to make the position of Marduk accord with the rank acquired by the secular rulers. As these emphasized their supremacy by grouping around them a court of loyal attendants dependent in rank and ready to do their master's bidding, so the gods of the chief centres and those of the minor local cults formed a group around Marduk; and the larger the group the greater was the reflected glory of the chief figure. Hence throughout the subsequent periods of Babylonian history, and despite a decided progress towards a monotheistic conception of divine government of the universe, the recognition of a large number of gods and their consorts by the side of Marduk remained a firmly embedded doctrine in the Babylonian religion as it did in the Assyrian religion, with the important variation, however, of transferring the rôle of the head of the pantheon from Marduk to Assur. Originally the patron god of the city of Assur (q.v.), when this city became the centre of a growing and independent district, Assur was naturally advanced to the same position in the north that Marduk occupied in the south.

The religious predominance of the city of Babylon served to maintain for Marduk recognition even on the part of the Assyrian rulers, who, on the political side likewise, conceded to Babylonia the form at least of an independent district even when, as kings of Assyria, they exercised absolute control over it. They appointed their sons or brothers governors of Babylonia, and in the long array of titles that the kings gave themselves, a special phrase was always set aside to indicate their mastery over Babylonia. "To take the hand of Bel-Marduk" was the ceremony of installation which Assyrian rulers recognized equally with Babylonians as an essential preliminary to exercising authority in the Euphrates valley. Marduk and Assur became rivals only when Babylonia gave the Assyrians trouble; and when in 689 B.C. Sennacherib, whose patience had been exhausted by the difficulties encountered in maintaining peace in the south, actually besieged and destroyed the city of Babylon, he removed the statue of Marduk to Nineveh as a symbol that the god's rule had come to an end.

His grandson Assur-bani-pal, with a view of re-establishing amicable relations, restored the statue to the temple E-Saggila in Babylon and performed the time-honoured ceremony of "taking the hand of Bel" as a symbol of his homage to the ancient head of the Babylonian pantheon.

But for the substitution of Assur for Marduk, the Assyrian pantheon was the same as that set up in the south, though some of the gods were endowed with attributes which differ slightly from those which mark the same gods in the south. The warlike nature of the Assyrians was reflected in their conceptions of the gods, who thus became little Assurs by the side of the great protector of arms, the big Assur. The cult and ritual in the north likewise followed the models set up in the south. The hymns composed for the temples of Babylonia were transferred to Assur, Calah, Harran, Arbela and Nineveh in the north; and the myths and legends also wandered to Assyria, where, to be sure, they underwent certain modifications. To all practical purposes, however, the religion of Assyria was identical with that practised in the south.

We thus obtain four periods in the development of the Babylonian-Assyrian religion: (1) the oldest period from c. 3500 B.C. to the time of Khammurabi (c. 2250 B.C.); (2) the post-Khammurabic period in Babylonia; (3) the Assyrian period (c. 2000 B.C.) to the destruction of Nineveh in 606 B.C.; (4) the neo-Babylonian period beginning with Nabopolassar (625-604 B.C.), the first independent ruler under whom Babylonia inaugurates a new though short-lived era of power and prosperity, which ends with Cyrus's conquest of Babylon and Babylonia in 539 B.C., though since the religion proceeds on its undisturbed course for several centuries after the end of the political independence, we might legitimately carry this period to the Greek conquest of the Euphrates valley (331 B.C.), when new influences began to make themselves felt which gradually led to the extinction of the old cults.

In this long period of c. 3500 to c. 300 B.C., the changes introduced after the adjustment to the new conditions produced by Khammurabi's union of the Euphratean states are of a minor character. As already indicated, the local cults in the important centres of the south and north maintained themselves despite the tendency towards centralization, and while the cults themselves varied according to the character of the gods worshipped in each centre, the general principles were the same and the rites differed in minor details rather than in essential variations. An important factor which thus served to maintain the rites in a more or less stable condition was the predominance of what may be called the astral theology as the theoretical substratum of the Babylonian religion, and which is equally pronounced in the religious system of Assyria. The essential feature of this astral theology is the assumption of a close link between the movements going on in the heavens and occurrences on earth, which led to identifying the gods and goddesses with heavenly bodies - planets and stars, besides sun and moon - and to assigning the seats of all the deities in the heavens.

The personification of the two great luminaries - the sun and the moon - was the first step in the unfolding of this system, and this was followed by placing the other deities where Shamash and Sin had their seats. This process, which reached its culmination in the post-Khammurabic period, led to identifying the planet Jupiter with Marduk, Venus with Ishtar, Mars with Nergal, Mercury with Nebo, and Saturn with Ninib. The system represents a harmonious combination of two factors, one of popular origin, the other the outcome of speculation in the schools attached to the temples of Babylonia. The popular factor is the belief in the influence exerted by the movements of the heavenly bodies on occurrences on earth - a belief naturally suggested by the dependence of life, vegetation and guidance upon the two great luminaries. Starting with this belief the priests built up the theory of the close correspondence between occurrences on earth and phenomena in the heavens. The heavens presenting a constant change even to the superficial observer, the conclusion was drawn of a connexion between the changes and the ever-changing movement in the fate of individuals and of nature as well as in the appearance of nature.