The Kabul Shahi dynasties also called Shahiya, ruled the Kabul Valley and the old province of Gandhara. Overtime the Shahi rulers converted from Buddhism to Hinduism, they ruled over a mixed population of people from both backgrounds in the time before the Islamic conquest of the area. For centuries the Hindu Shahi held out against the Muslim advance but were eventually defeated and retreated into Northern India. The Shahis left their coinage as perhaps their most important memorial. These coins were the first to bear the ubiquitous bull and horseman design. They were issued over two centuries or more.