Tsar is a title for the supreme ruler in several countries.

In Bulgaria , the title was used in 913?1422 and again in 1908?1946. The last tsar to rule Bulgaria was Boris III , who replaced Ferdinand I of Bulgaria 1918.

In Serbia , the title was used in 1346?1371. The last tsar to rule Serbia was Stephen Uro? V .

In the Russian Empire , the title was used from 1546 until 1721. Starting in 1721, the title of Russian emperors was imperator , but the word tsar remained in common use until the Russian Revolution in 1917. The last tsar to rule Russia was Nicholas II , who replaced Alexander III in 1894. The system of government used during the Tsardom of Russia and the Russian Empire was called Tsarist autocracy , also known as Tsarism.

Tsar is also spelled tzar , czar , and csar . It is the Eastern European word for caesar . It can be translated to emperor .