Tsar Ivan IV, also known as Ivan the Terrible, was the first ruler of Russia to be officially crowned as Tsar in 1547. He ruled from 1547 until his death in 1584 and is known for centralizing power and expanding the Russian territory. His reign saw significant reforms in government and the military, as well as the establishment of a more structured administration. Despite his accomplishments, Ivan IV is often remembered for his violent and erratic behavior, especially later in his life. He created a secret police force called the Oprichnina to suppress dissent, leading to widespread fear and persecution. His legacy is complex, marked by both achievements and brutality.