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.
John III, Count of Holstein-Plön
John III married on 27 January 1319 Catherine (c. 1300-1323), widow of John V, Margrave of Brandenburg-Salzwedel and daughter of Matilda of Brunswick and Lunenburg (Wolfenbüttel) and Henry III, Duke of Silesia-Glogau. Catherine and John had the following children:In second marriage his spouse was Merislawa of Schwerin-Wittenburg, daughter of Nicolotus I, Count of Schwerin-Wittenburg.