Alexander was heir to the king and Babylon marked the first and most important step in his progress to becoming the richest man in the world; Babylon and its farmland could feed the prodigalities of a King of Asia's court. Besides the country estates, so often in Persian hands, there was the city itself and its treasure, a reward of unimagined value; his meeting with Babylon would be crucial, his first encounter with an Asian city since victory had made him master of Persia's western empire. He could hardly have begun more auspiciously. Several miles north of the city's turreted walls, Mazaeus rode out to greet him, bringing his sons as a pledge of his loyalty, and the man who had led the Persian right wing only seven days earlier now offered to surrender Babylon, perhaps as prearranged.

Alexander was by no means as certain of the sequel as his historians implied. When Babylon's massive brick walls were in sight, he drew up his army as if for battle and ordered a prudent advance, hoping to seem a liberator, not another marauding king. He was bluffing, and he also feared a trap, but he was not to be disappointed in his hopes. As he came close, the gates of Babylon were thrown open and out streamed the city's officials down a road strewn with flowers and garlands and lined with incense-laden altars of silver. The Persian commander of the fortress brought herds of horses and cattle, leopards in cages and tame lions: behind him danced Babylon's priests and prophets, chanting their hymns to the sound of lutes and sackbuts. Less mistrustful, Alexander retained an armed guard and mounted the royal chariot; the natives followed him through the main city gate, and so to the Persians' palace where the ovation continued throughout the night.

Alexander's welcome in Babylon had been overwhelming, as striking a moment in his career as any pitched victory over Darius. Fear and the wish to appease a conqueror explain the Persian governors' meek surrender, but the citizens had forced their hand, and their motives were very much older. It is a mistake to invoke economics and point to the Persians' long dominance of Babylon's land and resources; under Persian rule, the rates of barter or bankers' interest in both Babylon and Egypt can be shown to have quadrupled or more within a hundred years, but in a society which used no coinage and where the vast mass of the population lived off what they could grow or be given by their masters, too much must not be made of a rise in the cost of luxuries or a drop in the value of a silver shekel. Under Persian rule deeds for the sale of slaves also increased noticeably in scale, and one class of serfs belongs only on farms of the Persian king; contracts provide ever more stringently against their attempts at escape. But many may have been foreign prisoners of war and slavery on the estates of an alien king was nothing new to Babylonians. Alexander was not heir to the rising of a long-oppressed proletariat; in a society where religion was strong, discontent would take less crude a form, inspired by the evident flourishing of the unjust or ungodly, rather than by visions of perpetual class war. There was none of the dogma to inspire such a protest. The genius of Babylon had been to compile where the Greeks would go on to compose; facts were collected, not framed by an abstract theory, and hence there was never a doctrine of class revolution to work on a slavery which Babylonians took for granted. For nearly two thousand years Babylon had observed, not explained; a Babylonian had already visited Plato's Academy in Athens, and Callisthenes is said to have copied and sent back to his relation, Aristotle, the records of Babylon's many astronomers, which stretched, according to rumour, for 34,000 years. Only in Greece would these records be used for a general theory of the heavens; there are prompt signs of their effects, for Callippus the astronomer soon calculated a more accurate length for the Greek year from a cycle which he began in July 330. He is said to have used Babylonian records and his dating implies these were Alexander's.

Babylon's surrender is also explicable from the gestures which Alexander made in return, probably by prior arrangement. Inside the city he gave the priesthood an audience and ordered the restoration of the temples which Xerxes had damaged, especially the famous E-sagila, which 'had been made to shine like the sun with gold and jewels', so its founder Nebuchadnezzar had written, 'while its ceilings were made of gilded Lebanon cedar and the floor of the Holy of Holies inlaid with red gold'. At the priests' suggestion, he paid sacrifice to the city's god Bel-Marduk, presumably clasping the hand of his statue to show that he received his power like the old Babylonian kings, from a personal encounter with the god. Once again, he had turned Xerxes's past misdeeds to his own advantage: as in Lydia or Caria or Egypt, he had also learnt through friends and interpreters where tact would be most appreciated.

In Babylon this respect for the temple communities had long been a precept of wise and kingly government, even under the brutal Assyrian empire of the eighth century B.C., but the example of history had been betrayed by Persian governors. Round the staff and properties of the temple were grouped the city assemblies, run by a council of priests but drawn from a wider class whose links with the temple were often weak or ancestral. These native assemblies had been forced to pay taxes to the Persian king, providing wine, beer, farm produce and gangs of labourers for the royal herds, buildings and gardens. No Persian king is known to have paid the customary tithe to the temples; as never before, temple slaves had been ordered to cut the king's reeds, bake his bricks and shear his sheep, while royal officials saw that the workers and taxes were sent as he commanded. Within sixy years of her conquest, Babylon had revolted four times against such interference, and in 482 Xerxes had sent his brother-in-law to punish Babylon for ever by breaching her walls, denying her the status of a satrapal capital and dropping her title of honour from his royal protocol. Temple lands had been confiscated, however briefly; the holy buildings of E-sagila and the tall sacred ziggurat of Etemenanki were damaged and the solid gold statue of the god Bel-Marduk was hauled away to be melted down. In the procession to welcome Alexander the priesthood and city officials danced behind the Persian commander, and in view of the past the attitude of these educated men was not surprising. In return, they won favours and as so often, what Alexander granted became a precedent for his successors. The Macedonian kings continued to give money for rebuilding the temples; they would call themselves King of the Lands, an ancient title of honour which referred specifically to Babylonia but had been dropped by the Persian kings since Xerxes; they respected the temple citizenry, allowing them to draw up their documents in their arcane scribal language and to be exempt from certain sales taxes, imposed on all other Greek-speaking citizens by a royal Overseer of Contracts. As privileged communities in a vast expanse of king's land, the Babylonian temple assemblies resembled the free Greek cities of Asia and certain royal favours were common to them both. As in Greek Asia, so in Babylon lands endowed on a royal courtier now had to be registered as part of a nearby temple dry's land, a contrast to the random gifts of a Persian king; presumably this privilege too first arose with Alexander.

Yet there were reservations. Alexander had ordered the rebuilding of the city's largest temple of Esagila, formerly more than 200 feet high, but he had not guaranteed its expenses; the money, it seemed, would be demanded from temple land, but the priesthood had long been enjoying these extra finances, because no temple buildings remained to absorb them. Moreover Xerxes's punisher still meant to rule, and his plans combined tact with firmness. Babylon was restored to its long-lost status as a satrapal capital, but tribute was still to be levied and garrisons kept in the city's fortress: these troops were divided between two officers, both with estates in Philip's Macedonia, one of them brother to a soothsayer who would have much in common with Babylon's many astrologers. The choice of satrap was more debatable: Mazaeus, Darius's renegade viceroy of Syria, was appointed to rule the province he had helped to surrender. This hardened Persian official was to be watched by two generals and a royal tax officer, but publicly he seemed to have lost very little of his dignity; he was once more a satrap, and probably silver coins continued to be minted and marked with his name, a Persian privilege which Alexander later tended to replace with standard designs of his own. This reinstatement was remarkable and perhaps rewarded an agreed betrayal of the