Peter III (February 21, 1728 – July 17, 1762) (Russian: Пётр III Фëдорович, Pyotr III Fyodorovitch) was tsar of Russia and Emperor of the Russian Empire for six months in 1762. According to most historians, he was mentally immature and very pro-Prussian, which made him an unpopular leader. He was supposedly assassinated as a result of a conspiracy led by his wife, who succeeded him to the throne as Catherine II.

Early life and character
After Peter gained the throne in 1762, he incurred many nobles' displeasure by withdrawing from the Seven Years' War and making peace with Prussia, in which Russia did not gain anything, in spite of Russia's occupation of Berlin and virtual victory in the war. He formed an alliance with Prussia and planned an unpopular war against Denmark in order to restore Schleswig to his Duchy of Holstein-Gottorp. It is also claimed that he wanted to force the Russian Orthodox Church to adopt Lutheran practices.
During Peter's short reign, Russia saw several minor but important economic reforms that encouraged development of Western-European style capitalism and mercantilism and to move away from Russia's traditional social practices of subjugating peasants and townspeople and reserving leading positions for nobility. He issued an edict abolishing the practice allowing industrialists to purchase serfs as workers for their enterprises. He also forbade the importation of sugar into Russia to stimulate domestic manufacturing.
Peter's major social reform was the introduction of the Liberty for Nobility, abrogating Peter the Great's policy of forcing all male members of Russian nobility to serve in the military or civil service without regard for individual preference for a particular occupation.
Catherine, along with her lover Grigori Orlov, planned to overthrow Peter, as she believed he would divorce her. The Leib Guard, on which Peter planned to impose harsher discipline, revolted and Peter was arrested and forced to sign his own abdication; Catherine became Empress with the support of most of the nobility. Shortly thereafter, Peter was killed while in custody at Ropsha. While Catherine did not punish the responsible guards, doubts remain as to whether she ordered the murder or not.