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 Pavlovna of Russia
Thus, Ekaterina was married to her first cousin Duke George of Oldenburg on 3 August 1809. George was the second son of Peter, Duke of Oldenburg and his wife, Duchess Frederica of Württemberg. The couple resided in Tver, where George had been appointed governor general. Catherine lived a lavish court life and entertained with balls, grand dinners and similar events in the pattern of the Imperial court, to create "a Small Saint Petersburg" in Tver. The couple were quickly blessed with two sons: Peter George (b. 1810) and Konstantin Friedrich Peter (b. 1812). Although the match had been arranged by their families, Ekaterina was devoted to her husband, and the marriage was harmonious. It was said that he was not handsome but Ekaterina cared for him deeply, and his death in 1812, due to typhoid fever, was a very severe shock to her. They had been married barely three years, and Ekaterina, now the mother of two infant sons, was only 24 years old.