Thus, as Darius awaited his feudal archers and horsemen he might be excused for the dreams which Greek historians attributed to him, the visions of the Macedonian camp aglow and of Alexander dressed in the Persian royal robe and vanishing into a Babylonian temple. Distressed feudal horsemen and a royal youth corps were hardly the ideal match for the Macedonian infantry and the Companion cavalry, but in the plains near the city, the Great King took refuge in numbers and consoled himself with counting his summoned troops. A circular enclosure was fenced off, able to hold some 10,000 men at a time. This was filled and emptied until the army had all passed through and the tens of thousands had been counted. Medes, Armenians, Hyrcanians, North Africans and Persians themselves: 'from dawn till dusk', in the exaggerated view of historians, 400,000 of these peoples filed through the stockade. Their true numbers cannot be estimated, nor do they matter for the sequel; but early one morning in late August or September, they decamped in their thousands and lumbered their way westwards among the canals of the well supplied Assyrian land.

To the sound of the trumpet, the Sacred Fire was hoisted forwards on its silver altars: priestly Magi followed chanting their traditional hymn; 365 young Wearers of the Purple strode behind them, 'equal to the number of days in the Persian year'. White horses from the Median fields tossed and stamped before the Chariot of Ahura-Mazda, their drivers dressed in white with matching whips of gold; the largest horse of all prepared to draw the Holy Chariot of the Sun. Immortal Guards, so called by the Greeks because their numbers never fell below 10,000, marched close behind in solemn order, as Royal Relations and Spear Bearers cleared the way for the chariot of the King. Gold beyond telling gleamed on its coachwork, the yoke was aflame with varied gems; on cither side rose pictures of the gods, among whom an eagle of gold, symbol of Ahura-Mazda, benevolently stretched its painted wings. Inside stood the bearded King Darius, thin-faced and dressed in a purple-edged tunic of white: from his shoulders streamed an embroidered cloak 'on which golden hawks were fighting with their curved beaks'; from his golden belt, hung a scimitar whose scabbard was made of a single gem; round his head, ran the fluted crown of the King of Kings, bound with 160 a ribbon of blue and white cloth. Cavalry and footmen paraded in attendance, protecting the chariots of the Queen and the Queen Mother who followed behind them; farther back fifteen mule-drawn wagons bore the eunuchs, the governesses and the royal children in their charge; 365 King's Concubines kept their distance, dressed for the occasion, while 600 mules and 300 camels edged them forwards, laden with a selection of the imperial treasures.

Back in the Macedonian camp, in the two months while Darius's army mustered, events had taken an unfortunate turn. After forcing the Cilician Gates in July, Alexander had hurried to seize Tarsus, rescuing it from burning by the Persians. He had marched fast in the heat, descending some 3,000 feet into an airless plain, and when he arrived in the city, he was understandably tired and dusty. Through Tarsus, run the yellowish waters of the Cydnus, a broad river which was said to be cool; Alexander, said Aristobulus, was already feverish. Others said that he swam, as yet in good health. But the local waters have a bad record; in 1189, the Calycadnus chilled Frederick Barbarossa, also rash enough to swim in the course of a Crusade. Within hours, Alexander developed a chill, hastened on by the cold water. His attendants laid him sleepless and shivering in his royal tent, but as he grew increasingly cramped, the doctors despaired of their treatment, until Philip the Greek stood forward, a man 'very much trusted in medical matters and not inconspicuous in the army'. He had attended Alexander as a boy and knowing his temperament, he proposed a purge with a strong medicine. Alexander was desperate to recover and gave his agreement.

While Philip assembled the necessary drugs, a letter was said to have been handed to Alexander from Parmenion; some say, implausibly, that it had arrived two days before and that Alexander had concealed it under his pillow. According to Parmenion, Philip the doctor had been bribed by Darius to kill his royal patient, but when Philip reappeared, Alexander disregarded any such warning. Handing Philip the letter, he took his glass of medicine and drank it down at the same time as Philip read the message. At once, Philip 'made it quite clear that nothing was wrong with his medicine: he was not in the least disturbed by the letter but simply ordered Alexander to obey any other instructions he might give him. If he did so, he would recover.' The purge eventually worked and Alexander's fever eased: 'Alexander then gave proof to Philip that he trusted him, convincing his other attendants that he was loyal to his friends in defiance of suspicion and that he was brave when faced by death.' Aristobulus may have agreed, though denying the swim.

The story of this letter has been disbelieved largely because it seems

too dramatic. But history is not only true when dull and though interventions by Parmenion are not to be trusted lightly, there is no outside evidence with which to challenge this telling scene. In legend, certainly, Parmenion is later made into a personal enemy of the doctor, or even into a cunning poisoner, hoping to kill Alexander and clear himself of guilt by his letter of warning beforehand. But these legendary embellishments do not prove that the story first arose to discredit him. Trust and daring are virtues to be expected in any great general and even if Alexander was not so indiscriminate in his loyalties as flattery implied, he was sharp to distinguish between true friends and false, prizing the former and purging the latter. It is much in favour of the story of doctor and letter that it brings this feature to the fore.

Alexander's sickness at Tarsus was a more serious delay than any of his historians made plain. Through the long weeks of July and August and on into mid-September, the king lay abed, apparently unaware that Darius's army had been summoned, let alone numbered and led out westwards from Babylon. Tactics, for Alexander, still centred on the coastline, and as he slowly recovered, there was enough to worry about at sea. Even without their Greek mercenaries, Memnon's successors were making themselves felt; they had sailed north to Tenedos, an island base for merchant shipping just off the Dardanelles, and they had taken it, again with a false reference to a peace of the past. Ten ships had been detached to the islands of the Cyclades off southern Greece, where they were to await overtures from Spartans and other disgruntled Greeks; Antipater was alarmed for the safety of Greece's coastline and had called out what warships he could, placing them under a Macedonian, probably the nephew of Alexander's nurse. A raid captured eight of the Persians' advance fleet and scared off the rest, but it could not be long before all hundred of the enemy ships came south. The two recruiting officers of Alexander's allied fleet were finding their business slow and difficult, perhaps because most Greeks preferred to stay neutral. Alexander could only press on with capture of Asian land bases, that desultory process which was bringing him nearer the ports of Syria and Phoenicia, although island harbours and the port at Halicarnassus were still open to the enemy behind him.

From now on, he was without detailed maps or local contacts, and for knowledge of what lay ahead he would surely consult the narrative of Xenophon's march, neatly detailed into marching-hours and distances. From it, he could deduce that the next enemy stronghold on the coast was the pass of the Pillar of Jonah from Cilicia into Syria some seventy miles distant, and on the basis of his reading he sent Parmenion at a leisurely pace round the coast to take it in advance, hoping that its complex of double turret walls and intervening river would not be too heavily guarded. Personally, he would march westwards in the opposite direction as soon as he felt fit.