He was the eldest son of Christian August, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (1696–1754) and his wife Duchess Louise Frederikke née Countess af Danneskiold-Samsøe (1699–1744). In 1754, his father died and Frederick Christian inherited Augustenborg Castle and Gråsten. However, these estates were deeply in debt. He waived his claims on the duchies of Schleswig and Holstein and in return the King of Denmark (who was also Duke of Schleswig and Holstein) granted him a favourable settlement. This allowed him to purchase Als and Sundeved, making him the largest landowner in Schleswig. He was also able to expand Augustenborg Castle, the family residence.
Frederick Charles Emil (8 March 1767 – 14 June 1841), Danish General, married Sofie Eleonore Fredericka of Scheel (1776–1836; daughter of Baron Jürgen Eric of Scheel);
Christian August (9 July 1768 – 28 May 1810), Danish general and, later, Crown Prince of Sweden as Karl August (died before he could ascend the throne);
Sophie Amelie (10 August 1769 – 6 October 1769);
Charles William (4 October 1770 – 22 February 1771).
Ancestors
Ancestors of Frederick Christian I, Duke of Schleswig-Holstein-Sonderburg-Augustenburg[1]
