Assur-bani-pal's victories were gained by his generals. He himself never appears to have taken the field in person. His tastes were literary, his habits luxurious. He was by far the most munificent patron of learning Assyria ever produced; in fact, he stands alone in this respect among Assyrian kings. The library of Nineveh was increased tenfold by his patronage and exertions; literary works were brought from Babylonia, and a large staff of scribes was kept busily employed in copying and re-editing them. Unfortunately, the superstition of the monarch led him to collect more especially books upon omens and dreams, and astrological treatises, but other works were not overlooked, and we owe to him a large number of the syllabaries and lists of words in which the cuneiform characters and the Assyrian vocabulary are explained.

When Assur-bani-pal died the doom of the Assyrian empire had already been pronounced. The authority of his two successors, Assur-etil-ilani-yukin and Sin-sar-iskun, or Saracos, was still acknowledged both in Syria and in Babylonia, where Kandalanu had been succeeded as viceroy by Nabopolassar. One of the contract-tablets from the north of Babylonia is dated as late as the seventh year of Sin-sar-iskun. But not long after this the Babylonian viceroy revolted against his sovereign, and with the help of the Scythian king, who had established himself at Ekbatana, defeated the Assyrian forces and laid siege to Nineveh. The siege ended in the capture and destruction of the city, the death of its king, and the overthrow of his empire. In B.C. 606 the desolator of the nations was itself laid desolate, and its site has never been inhabited again.

Nabopolassar entered upon the heritage of Assyria. It has been supposed that he was a Chaldæan like Merodach-baladan; whether this be so or not, he was hailed by the Babylonians as a representative of their ancient kings. The Assyrian empire had become the prey of the first-comer. Elam had been occupied by the Persians, the Scyths, whom classical writers have confounded with the Medes, had overrun and ravaged Assyria and Mesopotamia, while Palestine and Syria had fallen to the share of Egypt. But once established on the Babylonian throne, Nabopolassar set about the work of re-organising western Asia, and the military abilities of his son Nebuchadrezzar enabled him to carry out his purpose. The marriage of Nebuchadrezzar to the daughter of the Scythian monarch opened the road through Mesopotamia to the Babylonian armies; the Egyptians were defeated at Carchemish in B.C. 604, and driven back to their own land. From Gaza to the mouth of the Euphrates, western Asia again obeyed the rule of a Babylonian king.

The death of Nabopolassar recalled Nebuchadrezzar to Babylon, where he assumed the crown. But the Egyptians still continued to intrigue in Palestine, and the Jewish princes listened to their counsels. Twice had Nebuchadrezzar to occupy Jerusalem and carry the plotters into captivity. In B.C. 598 Jehoiachin and a large number of the upper classes were carried into exile; in B.C. 588 Jerusalem was taken after a long siege, its temple and walls razed to the ground, and its inhabitants transported to Babylonia. The fortress-capital could no longer shelter or tempt the Egyptian foes of the Babylonian empire.

The turn of Tyre came next. For thirteen years it was patiently blockaded, and in B.C. 573 it passed with its fleet into Nebuchadrezzar's hands. Five years later the Babylonian army marched into Egypt, the Pharaoh Amasis was defeated, and the eastern part of the Delta overrun. But Nebuchadrezzar did not push his advantage any further; he was content with impressing upon the Egyptians a sense of his power, and with fixing the boundaries of his empire at the southern confines of Palestine.

His heart was in Babylonia rather than in the conquests he had made. The wealth he had acquired by them was devoted to the restoration of the temples and cities of his country, and, above all, to making Babylon one of the wonders of the world. The temples of Merodach and Nebo were rebuilt with lavish magnificence, the city was surrounded with impregnable fortifications, a sumptuous palace was erected for the king, and the bed of the Euphrates was lined with brick and furnished with quays. Gardens were planted on the top of arched terraces, and the whole eastern world poured out its treasures at the feet of "the great king." His inscriptions, however, breathe a singular spirit of humility and piety, and we can understand from them the friendship that existed between the prophet Jeremiah and himself. All he had done is ascribed to Bel-Merodach, whose creation he was and who had given him the sovereignty over mankind.

He was succeeded in B.C. 562 by his son Evil-Merodach, who had a short and inglorious reign of only two years. Then the throne was usurped by Nergal-sharezer, who had married a daughter of Nebuchadrezzar, and was in high favour with the priests. He died in B.C. 556, leaving a child, whom the priestly chroniclers accuse of impiety towards the gods, and who was murdered three months after his accession. Then Nabu-nahid or Nabonidos, the son of Nabu-balasu-iqbi, another nominee of the priesthood, was placed on the throne. He was unrelated to the royal family, but proved to be a man of some energy and a zealous antiquarian. He caused excavations to be made in the various temples of Babylonia, in order to discover the memorial-stones of their founders and verify the history of them that had been handed down. But he offended local interests by endeavouring to centralise the religious worship of the country at Babylon, in the sanctuary of Bel-Merodach, as Hezekiah had done in the case of Judah. The images of the gods were removed from the shrines in which they had stood from time immemorial, and the local priesthoods attached to them were absorbed in that of the capital. The result was the rise of a powerful party opposed to the king, and a spirit of disaffection which the gifts showered upon the temples of Babylon and a few other large cities were unable to allay. The standing army, however, under the command of the king's son, Belshazzar, prevented this spirit from showing itself in action.

But a new power was growing steadily in the East. The larger part of Elam, which went by the name of Anzan, had been seized by the Persians in the closing days of the Assyrian empire, and a line of kings of Persian origin had taken the place of the old sovereigns of Shushan. Cyrus II., who was still but a youth, was now on the throne of Anzan, and, like his predecessors, acknowledged as his liege-lord the Scythian king of Ekbatana, Istuvegu or Astyages. His first act was to defeat and dethrone his suzerain, in B.C. 549, and so make himself master of Media. A year or two later he obtained possession of Persia, and a war with Lydia in B.C. 545 led to the conquest of Asia Minor. Nabonidos had doubtless looked on with satisfaction while the Scythian power was being overthrown, and had taken advantage of its fall to rebuild the temple of the Moon-god at Harran, which had been destroyed by the Scythians fifty-four years before. But his eyes were opened by the conquest of his ally the King of Lydia, and he accordingly began to prepare for a war which he saw was inevitable. The camp was fixed near Sippara, towards the northern boundary of Babylonia, and every effort was made to put the country into a state of defence.

Cyrus, however, was assisted by the disaffected party in Babylonia itself, amongst whose members must doubtless be included the Jewish exiles. In B.C. 538 a revolt broke out in the south, in the old district of the Chaldæans, and Cyrus took advantage of it to march into the country. The Babylonian army moved northward to meet him, but was utterly defeated and dispersed at Opis in the beginning of Tammuz, or June, and a few days later Sippara surrendered to the conqueror. Gobryas, the governor of Kurdistan, was then sent to Babylon, which also opened its gates "without fighting," and Nabonidos, who had concealed himself, was taken prisoner. The daily services in the temples as well as the ordinary business of the city proceeded as usual, and on the 3rd of Marchesvan Cyrus himself arrived and proclaimed a general amnesty, which was communicated by Gobryas to "all the province of Babylon," of which he had been made the prefect. Shortly afterwards, the wife—or, according to another reading, the son—of Nabonidos died; public lamentations were made for her, and Kambyses, the son of Cyrus, conducted the funeral in one of the Babylonian temples. Cyrus now took the title of "King of Babylon," and associated Kambyses with himself in the government. Conquest had proved his title to the crown, and the priests and god of Babylon hastened to confirm it. Cyrus on his side claimed to be the legitimate descendant of the ancient Babylonian kings, a true representative of the ancient stock, who had avenged the injuries of Bel-Merodach and his brother-gods upon Nabonidos, and who professed to be their devoted worshipper. Offerings to ten times the usual amount were bestowed on the Babylonian temples, and the favour of the Babylonian priesthood was secured. The images which Nabonidos had sacrilegiously removed from their shrines were restored to their old homes, and the captive populations in Babylonia were allowed to return to their native soil. The policy of transportation had proved a failure; in time of invasion the exiles had been a source of danger to the government, and not of safety.