Meanwhile Alexander's pursuits had varied with his information. As far as modem Isfahan he advanced steadily, taking the local tribesmen and a Persian palace in his stride; then, learning for the first time of Darius's flight, he hastened to Hamadan, a long week's march behind his prey and arrived there by mid-June, eager to gather supplies and continue northwards. Even in his haste he found time for two far-reaching changes: the proportion of the palace treasures which was being transported from Persia was to be centralized in Hamadan by a temporary guard of 6,000 Macedonians while all the allied Greek troops and Thessalian cavalry were to be released from military service. Able to replace his Greek allies with the recent reinforcements, Alexander thus took his leave of a myth which was becoming outdated; after its giddy climax at Persepolis, the slogan of a Greek revenge was not extended to the pursuit and capture of the Persian king, and in future the war was to be a personal adventure, not a public vendetta. On a private basis allies could enlist as adventurers and share in the excitement. Many did so, tempted by the promise of a bonus three times bigger than the splendid farewell paid to those who declined and received their agreed wages, a gigantic present in cash and an escort home to the sea coast, along with their spoils and souvenirs. Nine thousand talents and much finery were given away in a moment; lesser generals who found their units disbanded were given new commands, and Parmenion was to deposit the treasure with Alexander's friend Harpaltis in Hamadan and then march north-west with a large force against the Cadusians on whose help Darius had been depending. Expecting to meet in Gurgan, Alexander and his general took a brief farewell. They were never to see each other again.

By advancing northwards, Alexander was putting his quartermasters under severe strain. Persian documents prove that the main roads out to the Oxus were equipped with post-houses at every stage of the journey so that officials could enjoy regular meals if they had the right credentials. Alexander's generals, then, could be sure of food whatever the landscape, but the men had their wagons and little else, for the traders who followed the army would not find it easy to offer them the customary market in a land of desert tribes and no cities. They were entering months of short rations where the army would survive best if divided, and there was also the problem of pay. The wonderfully lavish donations at Hamadan promised well for the future, but there is nothing to show how Alexander paid his men for the next six years. Some treasure, at least, seems to have accompanied him, and a travelling mint was used by later kings; the gold bullion for a year's army pay would not have been impossibly bulky to transport from Hamadan to India, and a currency of silver ingots, valued by weight, appears to have been used across upper Iran under the Persian kings. The troops could be paid in this raw metal, for the total finds of Alexander's coinage in upper Iran are not impressive, and the small units of everyday exchange are particularly rare. Plunder and payment in kind must have been extremely important, although we hear most about them only in later Roman narratives, and perhaps the men served for a promise of huge rewards on returning home. But the amounts and availability of money can never be calculated, and a crucial side to the king and his soldiers' relationship is an insoluble mystery. At standard rates, which Alexander no doubt improved, the next six yean were immensely expensive; the treasury could stand them, but even if the methods of their funding are unknown, and likely to remain so, its intricacies and accounting should not be forgotten.

For eleven days Alexander led a force picked for its mobility northwards at furious speed from Hamadan; as Arab caravans later allowed nine days for the journey, he must have turned off the main road, perhaps hoping to catch Darius down a sidetrack. Disappointed, he returned to the Royal Road and rode into Rhagae where he rested for five days; many soldiers had already dropped out exhausted and several horses had been galloped to death.

It was stragglers once more who revealed what had happened. Two Babylonians, one of them Mazaeus's son, gave news of the arrest of Darius, and with a few picked horsemen Alexander at once raced eastwards to overtake the traitors. After two days' reckless gallop, resting only in the afternoon heat, he had reached Darius's last known camp on the edge of the Dasht-i-Kavir: Darius, he heard, had been stowed in a wagon and hustled as if for Shahroud by murderers who would abandon him in the last resort. Any time saved in the desert could prove decisive, so the fittest light infantry were mounted on horseback and ordered to follow a bold short cut across its fringes. Between dusk and dawn, forty miles of the salt-waste were covered, and at last as the morning heat began to take hold, a convoy of carts was to be seen in the green distance, shambling eastwards down the main road near modern Damghan. For the last time, the horses stumbled into a canter, enough at least to raise a dust and scare their unsuspecting prey. Only sixty men were at Alexander's side as the convoy was halted and the carts stripped for inspection. But search though they might, Darius was nowhere to be found.

Wearily, a Macedonian officer strayed to look for water by the roadside; searching, he came upon a mud-daubed wagon, abandoned by its team-He looked inside, and there lay a corpse, bound in the golden chains which signified a Persian king: like Yazdagird III, last of the Sassanid dynasty, in flight from the Arab invaders a thousand years later, Darius III, last of the Achaemenid kings, had been stabbed and deserted by his

own courtiers. Only in legend was he left enough breath to greet his discoverer and command Alexander's nobility. Serving officers insisted, conveniently, that Darius had died before Alexander could see him. The assassins had fled too far to be caught.

Left with his enemy's dead body, Alexander behaved remarkably. He stripped off his own cloak and wrapped it round the corpse. Darius was to be taken to Persepolis for a proper royal burial. The Persian prisoners were interviewed and the nobles were separated for release: the grand-daughter of Darius's royal predecessor was restored to her husband, a local aristocrat, and within days, Darius's own brother was enrolled as a Macedonian Companion. And yet, alive, Darius had been denounced as Alexander's enemy, 'who began their enmity in the first place', who 'would regain his family and his possessions only if he surrendered and pleaded on their behalf: it was a complete change of tone, and the soldiery must have watched it with amazement. Hugely generous gifts from the treasure captured with the convoy were distributed to reassure them.

By the death and capture of Darius, Alexander saw himself made heir to the empire which he had formerly come to punish. But the kingship of Persia was not to be assumed lightly; its roots went deep into history, and like the empire's government it had drawn freely on the background of its subject peoples. Alexander was about to succeed to traditions which he had already affronted. He would never come to terms with them, but it is important to realize what their example meant, and why he could not do them justice.

If Greeks had long denounced the Persian monarchy as slavish, and even explained it in terms of Asia's enfeebling climate, it was nonetheless a commendably versatile government. 'The Persians', Herodotus had written, 'admit foreign customs more readily than any other men', and the more that is known of them the more he is proved right. Two hundred years before Alexander, they had overthrown the empire of the Medes and annexed the ancient civilization of Babylon, but in each case they had availed themselves of their subjects' experience. From the Medes, they had acquired the arts of courtly comfort and secluded kingship, besides a legacy in language and architecture which is only now beginning to be recovered: from Babylon and Assyria, they had borrowed the ancient royal myths, whether the Tree of Life or the slaying of the Winged Lion of evil, which gave such sanctity to Persepolis, while at a humbler level, they had absorbed the law and bureaucracy for which their own illiterate pastoral life had not equipped them. As always, new needs had been met internationally: scribes from Babylon and Susa had kept the king's accounts in a language he could not speak, Greeks had served as his doctors, sculptors, interpreters and dancers, Carians and Phoenicians had manned his navy; the Magi of the Medes had managed his prayers and sacrifices, at least initially, while garrison service in the satrapies had brought Indians to Babylon, men from the Oxus to Egypt, Greek sailors to the Persian Gulf and Bactrians from outer Iran to Asia Minor. But skills and government service were not the end of this exchange.