Ivan IV Vasilyevich, called The Terrible (1530-84), grand duke of Moscow (1533-47) and czar of Russia (1547-84), one of the creators of the Russian state. He was the first Russian ruler to be formally crowned as czar. The first 13 years of Ivan's reign constitute one of the greatest periods of internal reform, external expansion, and centralization of state power in the history of Russia.

Ivan's reign after 1560 is remarkable more for the czar's repeated displays of erratic behavior and wanton brutality than for his statesmanship. He surrounded himself with a select group of noblemen, whom he allowed to exercise despotic power over his entire domain. In 1570 he ravaged the town of Novgorod and ordered the slaying of thousands of its inhabitants because they had been reported, on dubious authority, to be conspiring against him. Ten years later Ivan brought personal tragedy upon himself when, in a fit of anger, he struck and killed his eldest and favorite son.