The Oprichnina was a policy and territory established by Tsar Ivan IV, also known as Ivan the Terrible, in the 16th century. It lasted from 1565 to 1572 and aimed to consolidate the tsar's power by creating a separate state within Russia. The Oprichnina was characterized by its own administrative system, military forces, and a distinct legal framework. The Oprichniki, the enforcers of this policy, were known for their brutal tactics, including the persecution of perceived enemies and the confiscation of land. This period is marked by significant political repression and violence, contributing to the centralization of power in the Russian monarchy.