According to M. J. Olbrycht in a 2010 publication entitled “A companion to ancient Macedonia”:

Alexander the Great’s father Philip II “built his power and created many institutions to imitate those known from the Achaemenid [Persian] Empire,” because “the most immediate model of a great monarchy was Persia.” Although Alexander later conquered the Achaemenid Persian Empire, he and his court went through Iranization making “Iranians the mainstay of his army.” Alexander’s Indian War (327-325 BCE) “should be seen as a Macedonian-Iranian victory” given Alexander’s army were mostly Iranian.

[pic Columbia University: for educational purposes only]