Protection and supply of the largest baggage train to be seen in the Punjab was one urgent reason for fighting any natives who threatened along the east bank. Another was that Alexander meant to retain any conquests and clear the river, like earlier Persian kings, as the natural frontier for his empire. Even before the retreat from the Beas, he had been warned of unrest among a local tribe called the Malloi. They had long resisted attacks from Porus and threatened to oppose all invaders. As it was not Alexander's practice to leave any such enemy unscathed, he first subdued their neighbours on the early stages down the Jhelum and then planned to search out the Malloi by disembarking where that river met the Chenab. So far, the boatmen had been coping bravely, showing no fear in surroundings as strange as the Zambesi to its first European crew. But the natives began to talk nervously of the current and at a sudden bend in the river the explorers became aware of what they meant. The Chenab was flowing in on their left; they 'heard the roar of rapids and stayed their oars ... even the coxes fell into frightened silence, amazed by the noise ahead'. There was no hope of stopping before the whirlpools caught the tublike transport vessels and spun them round, loaded with corn and horses; they were heavy enough to survive, but the lighter warships were smashed in collisions, so much so that Alexander himself was forced to leave the royal flagship and swim for his life. The prospect of repairs was one more strain on the men's morale.

Rather than risk a native attack in the meantime, Alexander left his broken boats and wisely divided his forces: Hephaistion and the remaining fleet were to sail ahead in order to cut off fugitives. Ptolemy, the baggage, and all the elephants were to follow slowly behind, while Alexander took his toughest troops to surprise the gathering Malloi with a mere 12,000 men. The plan was in Alexander's boldest style and left no scope for suspect loyalties. He was determined to catch his enemy unprepared and, with admirable decision, he took the roughest and most unexpected route: towns intervened, and unless they surrendered they were shown no more mercy than usual. First, the troops stocked up with water from the Ayek river, and then they hurried across forty mud-baked miles of the Chandra desert in a single night, arriving in time to storm the unsuspecting inhabitants of Kot Kamalia fortress and hound down fugitives from marsh-bound Harapur. Driving the tribesmen east across the river Ravi, they made light work of steep Tulamba, a town which later proved too much for Tamurlane, and 'pressed on boldly' until all the citizens had been enslaved. Then they hesitated and wondered what was the point of it all.

They could hardly be blamed. They were a select corps cut off from the fleet and many of their infantry were over sixty years old; their toughness was unique but had been strained by three days' forced marching through the desert, yet Alexander would not leave the Malloi alone. Their capital overlooked the river Ravi and they could use it to harass his approaching baggage; they had summoned troops against him and they could not expect a son of Zeus to turn away. He knew that he had to go on and this time, one of his famous harangues was all that the weary required. The men heard him talk, no doubt of gods and heroes, of Heracles, Dionysus and his own past fortune; emotion gave in to arguments they knew so well and 'never before was so eager a shout raised from the ranks, as they bade him lead on with the help of heaven'. Not for the first time, Alexander had been saved by his powers of oratory, a gift he had so often observed in his father Philip.

A speech urged the army forwards, but before the towers of the nearby fortress of Aturi, they again began to hang back. When walls had been undermined and ladders placed against the citadel it was left to Alexander to climb them and 'shame the Macedonians into following one by one'. After a brief rest, the peak of the march was reached: a huge troop of Indians, 'at least 50,000', had gathered near a ford across the Ravi. Here, at last, were the Malloi, but they were so harassed by 2,000 Macedonian cavalry that they retired across the river and shut themselves in their greatest city, the fortress of Multan.

Multan is a name engraved on the hearts of every mid-Victorian Englishman in India; only a familiarity with Captain Edwardes's siege of Moolraj the Sikh in 1848 can explain what Alexander faced at this fateful moment in his career. Like Edwardes he was outnumbered by more than ten to one; he approached across the river and cordoned off the outer wall with his horsemen until the infantry could catch him up. Multan, then as now, was a double city, ringed by a wall near the river bank, and by an inner rampart which marked off the steep city-fortress in its centre. Its position was commanding and its view stretched over a river plain of mangoes, dates and pomegranates. Lushness was not its distinctive quality. Multan, say the natives to this day, is famed for four features: graveyards, beggars, dust and heat. In the early months of 325, Alexander was attacking a fort which was cursed for its uncongeniality.

When the infantry arrived, he led them against one of the small gates whose descendants, centuries later, were to give access to Edwardes's Scottish sappers. The gate broke and the Macedonians poured in: further round the wall, wrote Ptolemy, scoring a point against his enemy, 'the troops under Perdiccas hung back'. The next attack gave historians even more of an incentive to disagree. The objective was the citadel itself, which was to defy Edwardes for a fortnight longer than the outer town-Alexander commissioned the diggers and tunnellers and sent for the men with ladders. They were slow to stand forward, so he seized the nearest ladder and scaled the battlements himself; three senior officers followed, one of them carrying the sacred shield of Achilles which Alexander had taken as spoils from the temple at Troy. Indian defenders were brushed away by a few sword-thrusts until the king stood pre-eminent, as at Tyre, his armour gleaming against the background of the sky.

Down below, the ladders had broken and no more bodyguards could climb the wall. Alexander was cut off, under attack from nearby towers. A cautious man would have jumped back among his friends, but caution had never caused Alexander to spare himself for the loss of glory, and so he jumped down into the city. It was a memorable feat, though most irresponsible. He happened to land on his feet beside a fig-tree which gave him slight protection from enemy spears and arrows, but soon the Indians were upon him and he took to vigorous self-defence. He slashed with his sword and hurled any stones which lay to hand: the Indians recoiled, as his three attendants leapt down to join him, carrying the sacred shield. But Indian skills of archery were his undoing; his helpers were wounded, and an arrow, three feet long, struck him through his corslet into his chest. When an Indian ran forward to finish him off, Alexander had strength enough to stab his attacker before he struck home; then he collapsed, spurting blood, beneath the cover of his Trojan shield.

Outside, his friends had smashed the ladders and hammered the pieces as footholds into the clay wall; others hauled themselves up onto willing shoulders and gained the top of the battlement, where at the sight of their king beneath, they threw themselves down to shield him. The Indians had missed their chance, and as their enemies broke down the ban on the gates, they fled for safety. Macedonians were pouring in to avenge a grievance and, like the British smarting under two civilian murders two thousand years later, they massacred the men of Multan, down to the last of the women and children.

Inspection showed that Alexander's wound was extremely serious and it was with little hope that the Macedonians carried him away on his shield. According to Ptolemy, who was not present, 'air, as well as blood, was breathed out of the ait'; this would be certain proof that the arrow had punctured the wall of Alexander's lung, were there not a complication in the medical theory of the Greeks. As the circulation of the blood was unknown and the heart was widely believed to be the scat of intelligence, it could be argued that the veins were filled with air or vital spirit and that in the case of a wound, the air came out first, making way for the blood to follow. Ptolemy may have meant no more than that vital spirit had escaped from the king's veins, and hence the speed with which he fainted. But if the arrow did indeed pierce Alexander's lung, as its length suggests, his wound is a fact of the first importance. He would never escape from it; it would hamper him for the rest of his life and make walking, let alone fighting, an act of extreme courage. Never again after Multan is he known to have exposed himself so bravely in battle. True, no more sieges are described in detail, but when Alexander is mentioned he is almost always travelling by horse, chariot or boat. The pain from his wound, perhaps the lesions from a punctured lung, are a hindrance with which he had to learn to live. So too did his courtiers, but typically no historian refers to their problems again.