Frederick VII of Denmark
Born a prince of the House of Schleswig-Holstein-Sonderburg-Augustenburg and scion of a cadet-line descendant of the Danish royal House of Oldenburg, Christian August was the fiefholder of Augustenborg and Sønderborg. He was also a claimant to the rulership of the provinces of Slesvig and Holstein, and he was also a candidate to become king of Denmark during the succession crisis caused by the childlessness of King Frederick VII of Denmark. He lost the chance to ascend the throne to his distant kinsman, Prince Christian of Schleswig-Holstein-Sonderburg-Beck.