Tsar (also czar) is a Slavic term derived from the Latin caesar. Ivan III (Ivan the Great) (r. 1462-1505) was the first Russian ruler to begin using the title of tsar during his reign instead of the title Grand Prince of Moscow. His grandson, Ivan IV (Ivan the Terrible) (r. 1547-1584), was the first Russian ruler formally crowned as tsar.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Tsar/.