While Muḥammad-Sulṭān was recognized as khan throughout the territories dominated by his patron Mamai, he was in possession of the traditional capital Sarai only intermittently, in 1371–1373, 1374, and perhaps briefly in 1375–1376.
[2] This identification has had a long influence on subsequent historiography,[3] but has been disproved by recent scholarship, which established that Muḥammad-Sulṭān is to be distinguished from his successor as Mamai's protégé, Tūlāk (Teljak, Tjuljak, Tetjak in Russian sources).
[5] But the line of Batu is said to have ended in 1359 with the death of Berdi Beg, who had eliminated his close male kindred as potential rivals.
[13] More disappointment awaited Mamai, as his protégé Muḥammad-Sulṭān was chased out of Sarai in 1372 by Urus Khan, a distant cousin also descended from Jochi's son Tuqa-Timur, who had taken over the former Ulus of Orda in the eastern part of the Golden Horde.
These reverses eroded Mamai's authority over the Russian princes, and in 1374 Dmitrij of Moscow refused to recognize Muḥammad-Sulṭān as his overlord and to pay tribute to the khan and his beglerbeg.
[15] Mamai's difficulties and Muḥammad-Sulṭān reaching more mature years may have led to tension between them, possibly reflected in the khan's absence in Bolghar in 1377 and the end of his coinage at Orda.
[17] Whether this was so, Mamai replaced this khan with a new protégé, Tūlāk, in whose name a diploma of investiture was issued on 28 February 1379 for the would-be Russian Metropolitan Mihail (Mitjaj) on his way to Constantinople in 1379.