Old Russian monarchs, also known as Tsars, were the rulers of Russia from the 10th century until the 1917 revolution. They were autocrats who had absolute power over their subjects and were usually members of the Romanov dynasty. The most famous Tsar was Peter the Great, who modernized Russia and expanded its borders. Other notable Tsars include Ivan the Terrible, Catherine the Great, and Nicholas II, the last Tsar of Russia.