In view of the explanation offered for the silence maintained by Hammurabi and his successors regarding Nabu, we are justified in including Nabu in the Babylonian pantheon of those days. In later times, among the Assyrians, the Nabu cult, as already intimated, grows in popularity. The northern monarchs, in fact, seem to give Nabu the preference over Marduk. They do not tire of proclaiming him as the source of wisdom. The staff is his symbol, which is interpreted in a double sense, as the writer's stylus and as the ruler's sceptre. He becomes, also, the bestower of royal power upon his favorites. Without his aid, order cannot be maintained in the land. Disobedience to him is punished by the introduction of foreign rule. Political policy may have had a share in this preference shown for the minor god of Babylon. The Assyrian kings were always anxious to do homage to the gods of Babylon, in order to indicate their control over the southern districts. They were particularly proud of their title 'governor of Bel.'[133] On the other hand, they were careful not to give offence to the chief of the Assyrian pantheon—the god Ashur—by paying too much honor to Marduk, who was in a measure Ashur's rival. In consequence, as Hammurabi and his successors endeavored to ignore Nabu, the Assyrian rulers now turned the tables by manifesting a preference for Nabu; and obliged as they were to acknowledge that the intellectual impulses came from the south, they could accept a southern god of wisdom without encroaching upon the province of Ashur, whose claims to homage lay in the prowess he showed in war. Marduk was too much like Ashur to find a place at his side. Nabu was a totally different deity, and in worshipping him who was the son of Marduk, the Assyrian kings felt that they were paying due regard to the feelings of their Babylonian subjects. The cult of Nabu thus became widely extended in Assyria. Statues of the god were erected and deposited in shrines built for the purpose, although the fact was not lost sight of that the real dwelling-place of the god was in Borsippa. At the end of the ninth century B.C. this cult seems to have reached its height. We learn of a temple at Calah, and of no less than eight statues of the god being erected in the days of Ramman-nirari III., and the terms in which the god is addressed might lead one to believe that an attempt was made to concentrate the cult in Assyria on him.[134] This, however, was an impossibility. As long as Assyria continued to play the rôle of the subduer of nations, Ashur—the god of war par excellence—necessarily retained his position at the head of the Assyrian pantheon. The popularity of Nabu, which continued to the end of the Assyrian empire, and gained a fresh impetus in the days of Ashurbanabal, who, as a patron of literature, invokes Nabu on thousands of the tablets of his library as 'the opener of ears to understanding,' reacted on his position in the Babylonian cult. In the new Babylonian empire, which continued to so large a degree the traditions of Assyria, it is no accident that three of the kings—Nabupolassar, Nebuchadnezzar, and Nabonnedos—bear names containing the deity as one of the elements. While paying superior devotion to Marduk, who once more became the real and not merely the nominal head of the pantheon, they must have held Nabu in no small esteem; and indeed the last-named king was suspected of trying actually to divert the homage of the people away from Marduk to other gods, though he did not, as a matter of course, go so far as to endeavor to usurp for the son, the position held by the father. It is probably due to Assyrian influence that even in Babylonia, from the eighth century on, Nabu is occasionally mentioned before Marduk. So Marduk-baladan II. (721–710) calls himself the "worshipper of Nabu and Marduk," and similarly others. In official letters likewise, and in astronomical reports, Nabu is given precedence to Marduk, but this may be due to Nabu's functions, as the god of writing and the patron of science.
The Neo-Babylonian kings are not sparing in the epithets they bestow on Nabu, though they emphasize more his qualities as holder of the 'sceptre' than as lord of the 'stylus.' So Nebuchadnezzar declares that it is he 'who gives the sceptre of sovereignty to kings to rule over all lands.' In this capacity he is 'the upholder of the world,' 'the general overseer,' and his temple is called 'the house of the sceptre of the world.'
His name signifies simply the 'proclaimer,' or herald, but we are left in doubt as to what he proclaims—whether wisdom or sovereignty. Sometimes he appears as the 'herald' of the gods. In this rôle he receives the name of Papsukal (i.e., supreme or sacred messenger), and it may be that this function was a very old one. But, again, as god of fertility he could also be appropriately termed the 'proclaimer.' The question must, accordingly, be left open as to the precise force of the attribute contained in his name. Finally, an interesting feature connected with Nabu, that