At the Battle of Gaugamela (1 October 331 BC), in which Alexander defeated Darius III, Bessus commanded the left wing of the Persian army, chiefly composed of warriors from his Satrapy who had been mobilized before the Battle of Issus. The envelopment ordered by Darius failed and the Persians lost the battle after hours of fierce fighting. Bessus survived the battle and remained with his king, whose routed army eluded Alexander's forces and spent the winter in Ecbatana. The next year Darius attempted to flee to Bactria in the east. Bessus, conspiring with fellow satraps, deposed Darius and, according to sources, put him in golden chains. It is not clear whether Bessus was motivated primarily by personal ambition or by disillusionment with Darius as a leader. He may have intended to surrender the deposed king to the Macedonians, but Alexander ordered his forces to continue to pursue the Persians.