Pyotr Fyodorovich was born on February, 10th (21) 1728 in Kiel in Holstein Duchy (northern Germany). He was the son of duke Carl Frederic Golstein, a nephew of Charles XII of Sweden, and Grand Duchess Anna Petrovna of Russia, the daughter of Peter the Great and Catherine I of Russia.

In 1742 the Russian Empress Elizaveta Petrovna declared her nephew the successor to the Russian throne.

In 1745 he contacted marriage with Princess Sofia Frederica (the future Empress Catherine II).

After the death of Elizaveta Petrovna grand duke Pyotr Fyodorovich ascended the Russian throne as Emperor Peter III on December, 25th, 1761.

After half a year of reigning he was dethroned as a result of the palace revolution, which enthroned his wife, Catherine II, and was soon killed by guardsmen in Ropsha, near Saint Petersburg on 17 July [O.S. 6 July] 1762. For a long time historians were unanimous in their negative opinion of the personality and activities of Peter III. However, a better weighed approach appeared later, acknowledging a range of governmental merits of the emperor. During the reign of Catherine II numerous impostors passed themselves for Pyotr Fyodorovich (about 40 cases were recorded), whereas Yemelyan Pugachev became the most famous of them.