Alexander the Great and his Macedonian forces arrived in Afghanistan in 330 BCE after defeating Darius III of Persia a year earlier in the Battle of Gaugamela. Following Alexander's brief occupation, the successor state of the Seleucid Empire controlled the region until 305 BCE when they gave much of it to the Maurya Empire as part of an alliance treaty. The Mauryans controlled the area south of the Hindu Kush until they were overthrown in about 185 BCE. Their decline began 60 years after Ashoka's rule ended, leading to the Hellenistic reconquest by the Greco-Bactrians. Much of it soon broke away from them and became part of the Indo-Greek Kingdom. They were defeated and expelled by the Indo-Scythians in the late 2nd century BCE.