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.

Ivan was born in Moscow on Aug. 25, 1530, the grandson of Ivan III and the son of Basil III (1479–1533), whom he succeeded at the age of three. 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. In 1549 Ivan convoked the Zemsky Sobor, the first national representative assembly ever summoned by a Russian ruler. In the same year he initiated a comprehensive revision and modernization of the Russian law code. He conquered and annexed the Tatar khanates of Kazan (1552) and Astrakhan (1556), bringing the entire Volga River within the borders of Russia and ending the threat of these Tatar areas to Russia. The Livonian War (1558–83), an attempt to gain a foothold on the Baltic coast, was, however, unsuccessful.

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. In 1581, Ivan brought personal tragedy upon himself when, in a fit of anger, he killed his eldest and favorite son. In his later years, Ivan began the acquisition of Siberia after most of the Ob River Basin had been brought under Russian control (1581–83) by the cossack leader Yermak Timofeyevich (fl. 1579–85). Ivan died on March 18, 1584.