In spite of all difficulties, however, the Mongols and the savage tribes that followed in their wake [747] were at length brought to submit to the faith of those Muslim peoples whom they had crushed beneath their feet. Unfortunately history sheds little light on the progress of this missionary movement and only a few details relating to the conversion of the more prominent converts have been preserved to us. Scattered up and down throughout the length and breadth of the Mongol empire, there must have been many of the followers of the Prophet who laboured successfully and unknown, to win unbelievers to the faith. In the reign of Ogotāy (1229–1241), we read of a certain Buddhist governor of Persia, named Kurguz, who in his later years abjured Buddhism and became a Musalman. [748] In the reign of Tīmūr Khān (1323–1328), Ānanda, a grandson of Qūbīlāy and viceroy of Kan-Su, was a zealous Musalman and had converted a great many persons in Tangut and won over a large number of the troops under his command to the same faith. He was summoned to court and efforts were made to induce him to conform to Buddhism, and on his refusing to abandon his faith he was cast into prison. But he was shortly after set at liberty, for fear of an insurrection among the inhabitants of Tangut, who were much attached to him. [749] The author of the Muntakhab al-Tawārīkh asserts that Ānanda built four mosques in Khānbāligh (the modern Peking), which provided accommodation for 1,000,000 men at the time of the Friday prayer; but no credence can be given to this or to his other statements regarding the spread of Islam in China, in view of the fact that he represents Ānanda to have been the successor of Tīmūr Khān on the imperial throne and gives an entirely fictitious account of his descendants, several of whom are represented as having professed Islam, though none of the five had any existence except in the imagination of the writer. [750]