Nikita Minin (1605 – 1681, later adopting the name Nikon) was a religious leader who eventually became the Patriarch of the Russian Orthodox Church on the condition that he should have total control over matters of rituals.
In 1654, the Tsar asked Nikon to watch over his family and to supervise administration of the country while he was on a campaign in Poland and, when full on war broke out in 1657, the Tsar gave Nikon full sovereign powers.
His fall from grace started in approximately 1660 when he started to lose friends and allies due to his brutal treatment of people who did not agree with him. During his tenure as the Patriarch of the ROC, he introduced many reforms in an attempt to bring the Russian Orthodox Church into line with the Greek and other Eastern Orthodox Churches, believing that the others were more authentic. This caused major backlash from many. The people who didn’t agree with the reforms split from the ROC to become the Old Believers, who were then a main opposition to the ROC for 200 years. Nikon also believed in a theocratic state, meaning he thought that the Church should rule rather than the monarch. This, obviously, caused a massive clash with the Tsar, and Nikon was the deposed of in 1666. After his deposition, he Tsar introduced a new structure of leadership in which the state regained control over the church. Nikon’s reforms, however, remained in place.