[2] He was born into a Muslim family and served as the khan of the Khanate of Qasim before converting to Christianity and becoming an aide to Ivan IV of Russia.

[5] The first mention of Simeon is in the Supplement to the Nikon Chronicle in 1561 when he came to Moscow in the entourage of his aunt, Kochenei (baptized as Maria), when she married Ivan IV that year.

[6][7] The earliest evidence he was the khan of Qasim comes from a statement from the Russian ambassador to Constantinople, Ivan Novosiltsev, to the Ottoman sultan Selim II in 1570.

According to the most popular theory by contemporary diplomat Giles Fletcher, the Elder, Ivan aimed to confiscate the land that belonged to monasteries without attracting the ire of the Church.

[1] In 1612, as the result of a decree issued by Prince Dmitry Pozharsky and "on the advice of all the land" (Zemsky Sobor), Stefan was returned to the Kirillo-Belozersky Monastery.