Tsar Simeon Bekbulatovich was the nephew of Ivan IV's second wife, Manila Temriukovna. He was a Chingissid who had a remarkable career, first, as khan of Kasimov, then after entering Muscovite service, as head of the Muscovite army's "main regiment", as grand prince of Rus', and as grand prince of Tver'. He also married Anastasia Ivanovna Miloslavskaia. Finally he was tonsured as the monk Stefan and was buried in the Simonov Monastery. The episode that has attracted the most attention in the sources and in the scholarly literature was his appointment as grand prince of all Rus' between September 1575 and September 1576. Ivan IV held on to his other titles, including tsar of Kazan' and Astrakhan', but he also acquired an estate as the prince of Moscow under Grand Prince Simeon. In this article, I classified the primary source testimony into two categories: those accounts contemporary to the time of Ivan IV and those written after his death in 1584. After analyzing them and comparing them with the various historiographical explanations, I proposed that Ivan IV placed Simeon on the grand princely throne of Rus' as a legal maneuver to allow him to go after certain individuals in the ruling elite who he thought were plotting against him. These individuals who he suspected were mostly former members of the oprichnina. Ivan had claimed to the metropolitan in 1565 that he was being prevented from investigating and punishing certain individuals and again to foreigners in 1575 about the perfidiousness of his subjects. By having someone else serve as grand prince of Rus' who would give him the go ahead, he would be freed from constraints on his actions.
