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.
Peter III of Aragon
Like his father, Peter divided his kingdoms between his sons. He left Aragon to his eldest son, Alfonso, and Sicily to his second son, James. Peter's third son, Frederick, in succession to his brother James, became regent of Sicily and in due course its king. Peter did not provide for his illegitimate youngest son and namesake, Peter (1275 – 25 August 1296), who married Constança Mendes da Silva, daughter of Soeiro Mendes Petite, governor of Santarém in Portugal. This Peter left Spain for Portugal with his half-sister Elizabeth.