Peter or Ivan are two names that refer to the same person, TSAR or CZAR. TSAR and CZAR are both titles used to refer to the monarch of Russia. The title is derived from the Latin word Caesar, which means emperor. Peter I, also known as Peter the Great, was the first TSAR of Russia, reigning from 1682 to 1725. Ivan IV, also known as Ivan the Terrible, was the first TSAR of Russia to be crowned with the title of CZAR, reigning from 1547 to 1584. Both Peter and Ivan were powerful rulers who had a significant impact on the history of Russia.