Ghandahra is the name of an ancient Mahajanapada in northern Pakistan and parts of northern Punjab and Kashmir and eastern Afghanistan. Gandhara was located mainly in the vale of Peshawar, the Potohar plateau and on the northern side of the Kabul River. Its main cities were Peshawar and Taxila. The Kingdom of Gandhara lasted from the 6th Century BC to the 11th Century AD. In the sixth to fourth centuries BCE Gandhara was dominated under the Achaemenid Dynasty of Iran. The successors of Alexander the Great maintained themselves in Bactria and Gandhara from 322 BCE to about 50 BCE. Rejoined to India under the Maurya Dynasty, the Gandhara province became the object of intense missionary activity by the Buddhist emperor Asoka (reigned c. 273-232 BCE). In the first century AD the Kushans, a tribe of Scythian stock from north China made themselves masters of Gandhara. Their rule, however, was interrupted by the invasion of the Persian King Shapur I in AD 242, and the Buddhist civilization of Gandhara was finally completely destroyed by the White Huns, the Hephthalites, in the sixth century. It was conquered by Mahmood of Ghazni in 1021 AD, the name Gandhara disappeared.