He saved Alexander's life at the Battle of the Granicus in 334 BC and was killed by him in a drunken quarrel six years later.

[7] Cleitus was made a commander of the Greek Cavalry under Philip II, a position he would retain under Alexander the Great.

Specifically, Cleitus was given orders to take 16,000 of the defeated Greek mercenaries who formerly fought for the Persian king north to fight steppe nomads.

But sources agree that at this point Alexander retrieved a pike and threw it at Cleitus's chest, killing him.

Alexander was now employing eunuchs and was tolerant of such Persian customs as proskynesis, which was considered degrading by many in the Macedonian army.