Alexander was Macedonian; his father Philip II made improvements to the phalanx form and made other improvements, which made it possible for him to conquer neighboring areas, including Greece. When Alexander inherited the throne, he led his forces across to Anatolia and started his conquest of the Persian Empire. After his untimely death, his empire split up into pieces ruled by his various generals, the longest lasting was that of the Ptolemaic dynasty of Egypt.
I wish we knew more about ancient America. It is troubling to see South American ruins without detailed history to go with them.