Peter III of Russia
Empress Elizabeth arranged for Peter to marry his second cousin, Sophia Augusta Frederica (later Catherine the Great), daughter of Christian August, Prince of Anhalt-Zerbst and Johanna Elisabeth of Holstein-Gottorp. The young princess formally converted to Russian Orthodoxy and took the name Ekaterina Alexeievna (i.e., Catherine). They married on 21 August 1745. The marriage was not a happy one but produced one son, the future Emperor Paul, and one daughter, Anna Petrovna (20 December 1757 – 19 March 1759). Catherine later claimed that Paul was not fathered by Peter: that, in fact, they had never consummated the marriage. During the sixteen years of their residence in Oranienbaum, Catherine took numerous lovers, while her husband did the same in the beginning.
Catherine the Great
After the death of the Empress Elizabeth on 5 January 1762 (OS: 25 December 1761), Peter succeeded to the throne as Emperor Peter III, and Catherine became empress consort. The imperial couple moved into the new Winter Palace in Saint Petersburg. The tsar's eccentricities and policies, including a great admiration for the Prussian king, Frederick II, alienated the same groups that Catherine had cultivated. Peter intervened in a dispute between his Duchy of Holstein and Denmark over the province of Schleswig (see Count Johann Hartwig Ernst von Bernstorff). Russia and Prussia fought each other during the Seven Years' War (1756–1763), and Russian troops had occupied Berlin in 1760. Peter supported Frederick II, however, eroding much of his support among the nobility. Peter ceased Russian operations against Prussia, and Frederick suggested the partition of Polish territories with Russia.