On his deathbed, Memnon had appointed his Persian nephew and his deputy as temporary admirals and the pair of them had been fighting on boldly. By August, they had finally forced Mytilcne to surrender, 'urging the Mytilenaeans to become allies of Darius according to the peace of Antalcidas made with Darius', an extraordinarily crooked settlement, as this peace of Antalcidas, which had been sworn fifty-three years before to King Artaxerxes II, had left the Aegean islands free and in no way obliged to Persia. The treaty had perhaps been infringed often enough to be forgotten by a new generation of islanders; if so, Mytilene was rewarded for its poor sense of history with a garrison, a foreign commander, the return of rich exiles to half their property, a tyrant, and a punitive fine. The capture of Lesbos opened the fleet's path to the Dardanelles, but before the two admirals could pursue this, orders arrived for the delivery of most of their hired Greek troops. So, perhaps in mid-August, nearly two hundred ships were diverted cast along their open supply points at Cos and Halicarnassus to Tripolis on the coast of Syria where they could hand over their mercenaries to another nephew of Mcm-non. The ships were to be beached there, and the mercenaries were to march inland to Darius, '30,000 Greeks' according to Alexander's staff, a number which should be reduced or even halved.

The Persian admirals rejoined forces in the Aegean to continue their war with a mere 3,000 mercenaries and a hundred warships. Their prospects were much reduced, but Darius had not disturbed them unnecessarily, for he needed all possible infantry on land. From court, he had sent for the raw trainees of the Persians' youth-corps, boys who were conscripted in plenty for tree-cutting, hunting and wrestling as a preparation for army service. In the crisis, they were pitched into grown-up life, regardless of age or inexperience. Every ablebodied man within range was summoned, and from the land round the royal headquarters at Babylon the effects of such urgency can still be detected. By lifting the curtain on the Persians' empire, it is possible to lay bare the local problems of a call-up and see straight to the heart of an imperial soldier's life.

When the Persians had first conquered Babylon two hundred years before, they had divided its gloriously fertile land to suit their own interests. Much of it had been allotted to their servants and soldiers as a means of maintenance; the Persians faced the need for expensive and complex weaponry and as only land grants could finance this in a rural society without cash or coinage, they had introduced a feudal system which, like much that was sophisticated in the language and methods of Persian government, can be shown to trace back to their imperial predecessors, the Medes. As in the plains of Lydia, so in the plains of Mesopotamia families of foreign troopers from far afield had been settled on land grants, some seventy acres in the few cases where their extent is known, and arranged according to cantons of class or nationality, whether Arabs, Jews, Egyptians, Syrians or Indians, each supervised by district officers who were responsible for collecting the annual taxes due from the grant-holders to their king. Unlike the foreign colonists in Lydia and elsewhere, those in Babylonia recorded their business dealings on clay tablets in the dead Akkadian language and as baked clay can survive the ages, a hoard of their tablets has been found intact near the city of Nippur. Their information relates to the activities of a sharp firm of native entrepreneurs called the Murasu, which means, appropriately, a 'wild cat', and from their detailed evidence an important pattern can be extracted.

Three main types of land grant had been issued, horse land, bow land and chariot land; the very names are an insight into the Persian army, for the owners served as feudal archers, heavy cavalry and charioteers, complete with chariot and horse. All were liable for annual taxes, 'flour for the king', 'a soldier for the king' and 'taxes for the royal household', which were paid in weights of unminted silver. No family could sell any part of its land grant, and as many preferred to idle rather than to farm, increasingly they would strike a bargain with natives like the Murasu bank who were prepared to take a lease of their land grant, meet the yearly taxes from the proceeds and farm it for their own business profit. Unlike the colonists, the bankers were helped by a massive backing of men, silver, oxen, seeds, water rights and chain pumps. But though the taxes and the land could be leased to a wild cat entrepreneur, colonists in some, if not all, of the cantons were also liable for military service. The duty of military service was personal and had to be met from the owner's family; it could not be leased out with the land, and as the Murasu records show so neatly, ninety years before Alexander, complications were already at work within the system. They are unlikely to have changed by the time that Alexander invaded, for the system was still surviving under his Successors.

In one remarkable document, the problems are set out in detail. In 422 King Artaxerxes had summoned his colonists to attack the city of Uruk, but the summons had caught the Jewish owner of a land grant off his guard. Probably because of financial embarrassment, the Jew's father had been forced to adopt a member of the Murasu bank as his son, so that the banker could inherit a share in the family allotment, and as the land grant could only be owned by a member of the family, adoption was the one means of evading the king's law and endowing an outsider. When the father died, the adopted banker held one part of the farm, the true male heirs the rest. In 422 they were presented with the king's demand for silver, weaponry and the personal service of one family member as a fully equipped cavalryman, complete with horse. Fortunate in his banking 'brother', the Jew had struck an advantageous bargain; the wild cat bankers would not fancy fighting and so their adopted agent would finance the armour, silver tax, horse and, very probably, the groom, while the Jew would ride out at the risk of his life.

In the joy of his heart, Gadal-Iama the Jew has spoken thus to the son of the Murasu: the planted and ploughed fields, the horse land of my father, you now hold because my father once adopted your father. So give me a horse with a groom and harness, a caparison of iron, a helmet, a leather breastplate, a buckler, 120 arrows of two sorts, an iron attachment for my buckler, two iron spears and a mina of silver for provisions and I will fulfil the service-duties which weigh on our lands.

As the horseman owned no bow, the arrows were presumably to be handed in to the cashier and then distributed to owners of bow and chariot land.

But in summer 333, not every colonist would be sharing his land with a rich wild cat banker who could pay for his army outfit; the adoption of the banker is itself a sign, like the increasing number of leases and mortgages in the Murasu documents, that the colonists had found life more strenuous or awkward as the years went by. The annual tax was fixed, making no allowance for a bad harvest, and worse, the allotments remained the same size, though they had to pass to all male members of the family; even by 420, colonists were living on thirds, quarters, eighths or even fifteenths of their original grant. Their obligations remained the same, one fully turned-out soldier from the whole farm, even when the number of family mouths to be fed from the land had risen. Private Indians or Syrians could not meet the increase by intensive farming on the scale of the Murasu entrepreneurs, so the colonists' yearly surplus grew smaller as their home demand grew larger. They might fall into debt or adopt a banker as son; either way, they were no longer so capable of arming themselves to their king's expensive requirements. Horses and chariots need maintenance and an allotment split into fifteen parts is hardly a home for either; too much must not be built on the documents of one small area, especially as Babylonia was more urbanized than other satrapies, but it docs seem that one reason why the Great King had relied on hired Greek troops in the fourth century was the declining abilities of his own overcrowded colonists.