Now when Bel was pouring out the clear water, (i.e. thelight of day?)
And his diadem was taken off and lay upon the throne,
(Zu) seized the Tablets of Destiny,
He took Bel's dominion, the power of giving commands.
Then Zu fled away and hid himself in his mountain.
Bel was greatly enraged at the theft, and all the gods with him. Anu, lord of heaven, summoned about him his divine sons, and asked for a champion to recover the tablets. But though the god Ramman was chosen, and after him several other deities, they all refused to advance against Zu.
The end of the legend is unfortunately missing, but from a passage in another tale, the legend of Etana, we gather that it was the sun-god, Shamash, who eventually stormed the mountain-stronghold of Zu, and with his net succeeded in capturing the presumptuous deity.
This legend is of the Prometheus type, but whereas Prometheus (once a bird-god) steals fire from heaven for the behoof of mankind, Zu steals the Tablets of Destiny for his own. These must, of course, be regained if the sovereignty of heaven is duly to continue, and to make the tale circumstantial the sun-god is provided with a fowler's net with which to capture the recalcitrant Zu-bird. Jastrow believes the myth to have been manufactured for the purpose of showing how the tablets of power were originally lost by the older Bel and gained by Merodach, but he has discounted the reference in the Etana legend relating to their recovery.
Bel
We find a good deal of confusion in later Babylonian religion as to whether the name 'Bel' is intended to designate the old god of that name or is merely a title for Merodach. Khammurabi certainly uses the name occasionally when speaking of Merodach, but at other times he quite as surely employs it for the older divinity, as for example when he couples the name with Anu. One of the Kassite kings, too, speaks of "Bel, the lord of lands," meaning the old Bel, to whom they often gave preference over Merodach. They also preferred the old city of Nippur and its temple to Babylon, and perhaps made an attempt at one time to make Nippur the capital of their Empire.