If a sword wasn't Alexander's usual weapon, what would he have used in India when he scaled the wall and fought the Mallians until an arrow took him down? I always envisioned him swinging and stabbing with a sword. Would he have used a spear?
It would be a mistake to think that the Macedonians , including Alexander, had only one "usual" weapon. They would select a 'panoplia'/set of equipment for the task at hand. Thus when fighting mounted Alexander's primary weapon was a 12ft 'xyston'/lance, backed up by a 'xiphos'/sword as a secondary weapon. For defence he wore a metal helmet and body armour. No shield was carried at this time by Macedonian cavalry, the left, or bridle, hand being used to control the horse, and to use the 'xyston' two-handed.
On foot, Alexander would replace the cavalry 'xyston' with a traditional Macedonian 'longche' - a handy dual purpose thrusting or throwing spear some 5-6 ft long, or perhaps a 'Dory', the Greek 7-8ft thrusting spear, and add a shield and greaves to his defensive equipment. Outside the battlefield and its massed formations, the 'sarisa'/pike was too unwieldy for skirmishing or siege-fighting and the like, and the Macedonian heavy infantry fought with their traditional 'longche'.
At Mali, the wall had to be ascended by ladder, and one hand was needed for this, the other carrying the shield. Alexander may have taken a 'longche', held in the back of the shield, but clearly a spear is an encumbrance to a man climbing a ladder, and he may simply have had his sword, easily drawn on reaching the top of the wall, and indeed this is how Arrian says he fought.
This is one of the most dramatic episodes of Arrian's account, and hence is worth quoting at length.....
Arrian [Book VI.9]
"....some of the Macedonians tried to force an entry by undermining the wall, and others by placing scaling ladders against it, wherever it was practicable to do so. Alexander, thinking that the men who carried the ladders were too slow, snatched one from a man who was carrying it, placed it against the wall, and began to mount it, crouching under his shield. After him mounted Peucestas,the man who carried the sacred shield which Alexander took from the temple of the Trojan Athena and used to keep with him, and have it carried before him in all his battles. After Peucestas, by the same ladder ascended Leonnatus the 'somatophylax'/ body-guard ; and up another ladder went Abreas, one of the soldiers , who received double pay for distinguished services. The king was now near the battlement of the wall, and leaning his shield against it was pushing some of the Indians within the fort, and had cleared that part of the wall, by killing others with his sword. The 'hypaspists'/ guards becoming very anxious for the king's safety, pushed each other with ardour up the same ladder and broke it ; so that those who were already mounting fell down and made the ascent impracticable for the rest. Alexander then, standing upon the wall, was being assailed all round from the adjacent towers ; for none of the Indians dared approach him. He was also being assailed by the men in the city, who were throwing darts/javelins at him from no great distance;
for a mound of earth happened to have been heaped up there opposite the wall. Alexander was conspicuous both by the brightness of his weapons and by his extraordinary display of audacity. He therefore perceived that if he remained where he was, he would be incurring danger without being able to perform anything at all worthy of consideration ; but if he leaped down within the fort he might perhaps by this very act strike the Indians with terror, and if he did not, but should only thereby be incurring danger, at any rate he would die not ignobly after performing great deeds of valour worthy of recollection by men of after times. Forming this resolution, he leaped down from the wall into the citadel ; where, supporting
himself against the wall, he struck with his sword and killed some of the Indians who came to close quarters with him, including their leader, who rushed upon him too boldly. Another man who approached him he kept in check by hurling a stone at him, and a third in like manner.
Those who advanced nearer to him he again kept off with his sword ; so that the barbarians were no longer willing to approach him, but standing round him cast at him from all sides whatever any one happened to have or could get hold of at the time.
Meantime Peucestas and Abreas, the soldier entitled to double pay, and after them Leonnatus, being the only men who happened to have scaled the wall before the ladders were broken, had leapt down and were fighting in front of the king. Abreas, the man entitled to double pay, fell there, being shot with an arrow in the forehead. Alexander himself also was wounded with an arrow under the breast through his breastplate into the chest, so that Ptolemy says air was breathed oat from the wound together with the blood. But although he was faint with exhaustion, he defended himself, as long as his blood was still warm. But the blood streaming out copiously and without ceasing at every expiration of breath, he was seized with a dizziness and swooning, and bending over fell upon his shield. After he had fallen Peucestas defended him, holding over him in front the sacred shield brought from Troy; and on the other side he was defended by Leonnatus. But both these men were themselves wounded, and Alexander was now nearly fainting away from loss of blood. For the Macedonians had experienced great difficulty in the assault also on this account, because those who saw Alexander being shot at upon the wall and then leaping down into the citadel within, in their ardour arising from fear lest their king should meet with any mishap by recklessly exposing himself to danger, broke the ladders. Then some began to devise one plan and others another to mount upon the wall, as well as they could in their state of embarrassment, some fixing pegs into the wall, which was made of earth, and suspending themselves from these hoisted themselves up with difficulty by their means; others got up by mounting one upon the other. The first man who got up threw himself down from the wall into the city, and so on in succession ; and when they saw the king lying there on the ground they all raised a loud lamentation and howl of grief. Now ensued a desperate conflict around his fallen body, one Macedonian after another holding his shield in front of him. In the meantime some of the soldiers having shivered in pieces the bar by which the gate in the space of wall between the towers was secured,
entered the city a few at the time , while others, inasmuch as a gap had been made in the gate, put their shoulders under it and forced it into the space inside the wall, and thus laid the citadel open in that quarter.
Hereupon some o£ them began to kill the Indians, all of whom they slew, sparing not even a woman or child. Others carried off the king, who was lying in a faint condition, upon his shield ; and they could not yet tell whether he was likely to survive. Some authors have stated that Critodemus, a physician of Cos, an Asclepiad by birth made an incision into the injured part and drew the weapon out of the wound. Other authors say that as there was no physician present at the critical moment, Perdiccas, the 'somatophylax'/body-guard, at Alexander's bidding, made an incision with his sword into the wounded part and removed the weapon. On its removal there was such a copious effusion of blood that Alexander swooned again ; and the effect of the swoon was, that the effusion of blood was staunched........."
c.f. Curtius IX.18-23 ; Plutarch 'Alexander' 63; Diodorus (xvii. 98, 99) ; Justin (xii. 9). for other accounts of this famous incident.