Sultan Giyas al-Din Mohammed Öz Beg (), better known as Uzbeg, Uzbek or Ozbeg (1282–1341), was the longest-reigning khan of the Golden Horde (1313–1341), under whose rule the state reached its zenith. He was succeeded by his son Tini Beg. He was the son of Toghrilcha and grandson of Mengu-Timur, who had been khan of the Golden Horde from 1267 to 1280. Hence, he was a direct descendant of Genghis Khan. Öz Beg Khan moved his residence to Mukhsha (today a village of Narovchat in Penza Oblast). Coronation and conversion to Islam by the horde Öz Beg's father Togrilcha was one of the Genghisid princes that overthrew Tode-Mengu (r. 1280–1287). Later, he was executed by his brother Toqta (1291–1312). Toqta took Togrilcha's widow for wife and sent his son Öz Beg to exile in a distant region of the Golden Horde: either Khorazm or the country of Circassians. Converted to Islam by Ibn Abdul Hamid, a Sunni Sufi Bukharan sayyid and sheikh of the Yasavi order, Öz Beg assumed the throne upon the death of his uncle Toqta in January 1313 with the help of the former Khans' vizier Temur Qutlugh and of Bulaghan (or Bayalun) khatun. At first, many Mongol nobles were against him and organized a plot to kill the new khan. Öz Beg discovered the plot and crushed the rebels. His adoption of Islam as a state religion led to a conspiracy of Shamanist and Buddhist princes, whom he subdued severely. Öz Beg determinedly spread Islam among the Golden Horde and allowed missionary activities to expand in the surrounding regions. Öz Beg found out that his competitor was backed by the envoys of the Great Khan Ayurbarwada Buyantu and this fact helped deteriorate his relationship with the Yuan dynasty. The last of his rebellious relatives was shamanist Ilbasan of the eastern half of the Golden Horde, who was murdered in 1320. Öz Beg installed the Muslim Mubarak Khwaja as a replacement to the throne of the White Horde, but he discouraged their independence. In the long run, Islam enabled the Khan to eliminate inter-factional struggles in the Horde and to stabilize state institutions. Russian scholar Lev Gumilev wrote that in this manner was Öz Beg able to turn the khanate into a sultanate. From Öz Beg onwards, the khans of the Golden Horde were all Muslim. Öz Beg was very tolerant of Christians as exemplified by a