 Uyghur power declined, and three main regional kingdoms vied for power around Xinjiang, namely the Buddhist Uyghur Kara-Khoja, the Turkic Muslim Kara-Khanid, and the Iranian Buddhist Khotan.Eventually, the Turkic Muslim Kara-Khanids prevailed and Islamized the region.In the 13th century it was part of the Mongol Empire.