Karl Friedrich I, Duke of Schleswig-Holstein-Gottorp
Answer
Catherine II Of Russia and Peter III Of Russia were married between 1745 and 1762. Peter III Fyodorovich was Emperor of Russia from 5 January 1762 until 9 July of the same year, when he was overthrown by his wife, Catherine II.
Catherine II of Russia Mind Meld: 23 Questions to test your cognitive skills