This belief in his divinity was instilled in him by Olympias who also told him that his was a virgin birth as she were miraculously impregnated by Zeus himself. His birth was associated with wonderful indications and wonders, for instance a shiny star gleaming over Macedonia that night as well https://garrettrthsr.tribunablog.com/the-smart-trick-of-spirituality-that-nobody-is-discussing-50791996