| Peter August | |
| Duke of Schleswig-Holstein-Sonderburg-Beck | |
| Reign: | 22 September 1774 – 24 February 1775 |
| Full Name: | Peter Augustus Frederick German: Peter August Friedrich |
| House: | Schleswig-Holstein-Sonderburg-Beck |
| Spouse: | Princess Sophie of Hesse-Philippsthal Countess Natalia Nikolaievna Golovina |
| Issue: | Karl Anton August Catherine |
| Father: | Frederick Louis, Duke of Schleswig-Holstein-Sonderburg-Beck |
| Mother: | Duchess Louise Charlotte of Schleswig-Holstein-Sonderburg-Augustenburg |
| Birth Date: | 7 December 1697 |
| Birth Place: | Königsberg, Prussia |
| Death Place: | Reval, Russia |
Peter August Friedrich, Duke of Schleswig-Holstein-Sonderburg-Beck (7 December 1697 – 22 March 1775) was a Duke of Schleswig-Holstein-Sonderburg-Beck.
Born in Königsberg, Duchy of Prussia, as the fifth and youngest son of Frederick Louis, Duke of Schleswig-Holstein-Sonderburg-Beck and his wife, Duchess Louise Charlotte of Schleswig-Holstein-Sonderburg-Augustenburg (1658-1740).[1] He was named after the Russian tsar Peter the Great, who stood by proxy as his godfather after Duke Frederick asked him to do so. It was one of the first family ties established between the Eastern Orthodox Romanov dynasty and Protestant rulers of Europe, predating the German marriages of Peter's own children and nieces.
Peter August became Governor General of Reval (Tallinn), Governor of Estonia, and a Field Marshal in the Russian Imperial Army.[1] He died in Reval, Russian Empire.
He was only the titular duke, because he did not inherit the Haus Beck, Ulenburg, Herford and the domain that belonged to this line of the family. It had been inherited by his father's older brother, Duke August (1652–1689), and nephew Frederick William I (1682–1719), and was then sold by the latter's widow, Duchess Antoinette Josefa (1692-1762) to Peter August's older brother, Duke Frederick William II (1687–1749), in 1732.[2] But he re-sold it in 1745 to Baroness Magdalena Dorothea von Ledebur-Königsbrück (d. 1750). Thus, by the time that Peter August became the head of this cadet branch of the House of Oldenburg, he was Duke of Schleswig-Holstein-Sonderburg-Beck in name only.[2]
He is the male line ancestor of Margrethe II of Denmark, Harald V of Norway, Constantine II of Greece and Charles III of the United Kingdom and the Commonwealth realms, as well as previous Kings of Denmark, Kings of Greece, Kings of Norway and future Kings of the United Kingdom of Great Britain and Northern Ireland.[3]
Peter August married Princess Sophie of Hesse-Philippsthal (1695-1728), the daughter of Philip, Landgrave of Hesse-Philippsthal and his wife, Countess Katharina Amalie of Solms-Laubach (1654-1736), at Rinteln on 5 September 1723.[1] Sophie died on 8 May 1728 at age thirty-three.[1] Peter August and Sophie had two sons and one daughter:
He married secondly Countess Natalia Nikolaievna Golovina (1724-1767), granddaughter of Count Fyodor Golovin, daughter of Count Nicholas Fedorovich Golovin (1695-1745) and his wife, Sophie Pushkina (1700-1745), on 15 March 1742. The couple had two sons and one daughter: