- first czar of Russia 1547–84.
- known as Ivan the Terrible. 1530–84, grand duke of Muscovy (1533–47) and first tsar of Russia (1547–84). He conquered Kazan (1552), Astrakhan (1556), and Siberia (1581), but was defeated by Poland in the Livonian War (1558–82) after which his rule became increasingly oppressive
