Paul I (Russian: I Pavel I Petrovich; 1 October [O.S. 20 September] 1754 23 March [O.S. 11 March] 1801) was Emperor of Russia from 1796 until his assassination. Officially, he was the only son of Peter III and Catherine the Great, although Catherine hinted that he was fathered by her lover Sergei Saltykov. Paul remained overshadowed by his mother for most of his life. He adopted the laws of succession to the Russian thronerules that lasted until the end of the Romanov dynasty and of the Russian Empire. He also intervened in the French Revolutionary Wars and, toward the end of his reign, added Kartli and Kakheti in Eastern Georgia into the empire, which was confirmed by his son and successor Alexander I.

He was de facto Grand Master of the Order of Hospitallers from 1799 to 1801 and ordered the construction of a number of Maltese thrones. Paul's pro-German sentiments and unpredictable behavior made him unpopular among Russian nobility, and he was secretly assassinated by his own officers.

Tsar ( or ), also spelled czar, tzar, or csar, is a title used to designate East and South Slavic monarchs. In this last capacity it lends its name to a system of government, tsarist autocracy or tsarism. The term is derived from the Latin word caesar, which was intended to mean "emperor" in the European medieval sense of the term—a ruler with the same rank as a Roman emperor, holding it by the approval of another emperor or a supreme ecclesiastical official (the Pope or the Ecumenical Patriarch)—but was usually considered by western Europeans to be equivalent to "king"."Tsar" and its variants were the official titles of the following states:

Bulgarian Empire (First Bulgarian Empire in 919–1018, Second Bulgarian Empire in 1185–1396), and also used in Tsardom of Bulgaria, in 1908–1946

Serbian Empire, in 1346–1371

Tsardom of Russia, in 1547–1721 (replaced in 1721 by imperator in Russian Empire, but still remaining in use, also officially in relation to several regions until 1917)The first ruler to adopt the title tsar was Simeon I of Bulgaria. Simeon II, the last tsar of Bulgaria, is the last person to have borne the title tsar.