Ivan IV, also known as Ivan the Terrible, was the first Tsar of Russia. He ruled from 1547 until his death in 1584. Ivan is remembered for his centralization of power, expansion of the Russian state, and his often brutal and erratic behavior. He is known for his role in the conquest of the Khanates of Kazan, Astrakhan, and Siberia, which greatly expanded the Russian Empire. However, his reign was also marked by periods of extreme violence, including the infamous Massacre of Novgorod in 1570. Ivan's legacy is complex, as he is seen as both a visionary leader and a ruthless tyrant.