What helped Alexander expand his empire

Firstly, without the seasoned veterans and the dominated Greek Empire Philip, his father gained, Alexander would have had much less of a chance to go to Persia for his revenge war. He probably would have had to do what Phillip did for him and assert control over Greece, especially the Peloponnese. Secondly, Alexander’s divine heritage (allegedly son of Zeus) gained him respect along with his burning ambition and meglomanic attitude that was seen as heroic spirit. Thirdly, Alexander did not value worldly goods over his legacy or the goals he was trying to accomplish; therefore he allotted much of the crown lands to his soldiers and often was generous with his gift-giving to friends and those who showed him particular heroism; these attributes made his men much more eager to follow him. Lastly, Alexander showed the mettle of a true Homeric Greek hero: Kleos, Arete, Time and Aidos. He took after Achilles (kept The Iliad under his pillow) and therefore earned incredible respect. His conquer-as-you-go approach to the Persians as well as his fair treatment and assimilation with them also helped, although this made him unpopular with factions of his army and resulted in assassination attempts and the death of Cleitus the Black. For more, see Plutarch; Nine Lives, Alexander, Diodoros, Appian and Bosworth.