In medieval Russia the title tsar referred to the supreme male monarch, or king, particularly the Byzantine emperor, who was considered the head of the Orthodox Christian world.
The first recorded the word Tsar was in 1545-1455 from Russian Tsar. Nicholas II (1868-1918) was the last czar of Russia. Nicholas II was from a long line of Romanov rulers. He was overthrown in 1917 — but the word till being used for the head of a big government program.
The Tsar, 16th century by Sergey Ivanov
