The Islamic world expanded into Central Asia during the 8th century, under the Umayyad Caliphate, while its successor the Abbasid Caliphate put a halt to Chinese westward expansion at the Battle of Talas in 751 (near the Talas River in modern-day Kyrgyzstan). However, following the disastrous An Lushan Rebellion (755–763) and the conquest of the Western Regions by the Tibetan Empire, the Tang Empire was unable to reassert its control over Central Asia. Contemporary Tang authors noted how the dynasty had gone into decline after this point. In 848 the Tang Chinese, led by the commander Zhang Yichao, were only able to reclaim the Hexi Corridor and Dunhuang in Gansu from the Tibetans. The Persian Samanid Empire (819–999) centered in Bukhara (Uzbekistan) continued the trade legacy of the Sogdians. The disruptions of trade were curtailed in that part of the world by the end of the 10th century and conquests of Central Asia by the Turkic Islamic Kara-Khanid Khanate, yet Nestorian Christianity, Zoroastrianism, Manichaeism, and Buddhism in Central Asia virtually disappeared.