In 334 BC, Alexander the Great began his invasion of the Persian Empire and subsequently defeated the Persians in several battles before looting and destroying their capital, Persepolis, by fire in 330 BC. With the Persian Empire now effectively under Alexander's control, Alexander then decided to pursue Darius. Before Alexander reached him, however, Darius was killed by his relative Bessus, who was also the satrap of Bactria.
In 334 BC, Alexander the Great began his invasion of the Persian Empire and subsequently defeated the Persians in several battles before looting and destroying their capital, Persepolis, by fire in 330 BC. With the Persian Empire now effectively under Alexander's control, Alexander then decided to pursue Darius. Before Alexander reached him, however, Darius was killed by his relative Bessus, who was also the satrap of Bactria.