While many things can be attributed to Alexander the Great's military genius and the remaining plans of the deceased King Phillip, none of that would have been possible for Alexander to conduct without the thousands of troops that committed themselves to his army. There were many different kinds of soldier in Alexander's army, with each having different purposes and abilities dependant on their training and status.
There were two main categories, the infantry and the calvary, which were each made up of 32,000 and 5,100 soldiers respectively, along with technical support and Alexander's personal staff. The mounted cavalry was made up of the Companion Cavalry, the Thessalian Cavalry, the Greek Light Horses, and the Thracians and Paeonninas. The Companion Cavalry was made up of 1,800 soldiers, which included the Royal Squadron, led by Alexander and his personal bodyguard. Besides the Royal Squadron, there were 7 squadrons of 215 soldiers each. The Royal Squadron was made of 300 members, likely excluding some of Alexander's personal staff who weren't soldiers. However, from Alexander's staff were 8 personally selected bodyguards known as the Somatophylates, while the others from Alexander's staff were the Hetairoi, 100 'companions,' who were Alexander's unofficial council, including Eumenes, who kept his journal.
The foot soldiers, the infantry, were made up of the Phalanx, the Hypaspists, the Greek troops, Thracians and Illyrians, Agrianians, and the Cretan Archers. The numbers resulted in them having a total of 32,000 soldiers, with the Phalanx supporting 6 battalions of 1,500 each, the Hyaspists with 3 battalions of 1,000 each, the Greek troops having 12,000 members, 5,000 of which were mercenaries, the Thracians and Illyrians having 6,500, the Agrianians having 1,000, and the Cretan Archers having 500 members. Most of the soldiers wielded javelins, bows, or the sarissa, a Macedonian creation. The sarissa were made of long wood, found from trees that grew explicitly in Macedonia, with spikes on the end to act as an extremely long spear. It was able to maintain a distance between the Phalanx, the soldiers who wielded them, and the enemy, which enabled archers and disabled their attackers from attacking them while they could charge with the sarissa. It is estimated that the sarissa was 15 feet, or 4.5 metres, long. The cavalry also carried a sarissa, however theirs measured at around 12 feet instead of 15, likely to allow more freedom in movement and attacks.
The sheer number of soldiers alone is what helped Alexander's conquership, that and the dedication of his own soldiers to his cause. Credit can be lain to the works of the military leaders in terms of their planning, strategies and tactics. However, if not for the contributions of the soldiers of Alexander's army, it is unlikely he would have succeeded in his campaign of conquership over the Persian Empire.
