[1] He is best known for serving as Crown Prince of Sweden briefly in 1810, adopted by Charles XIII, before his sudden death from a stroke.

[2] He was born at Augustenborg Palace in July 1768 as the son of Friedrich Christian I, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (1721–1794) and Princess Charlotte of Schleswig-Holstein-Sonderburg-Plön (1744–1770).

[citation needed] The new king Charles XIII accepted the new, liberal Constitution, which was ratified by the Riksdag of the Estates the same day.

The choice of Christian August was supported by Charles XIII as well as three of the estates of the realm; the Clergy, Burghers and Peasants.

However, the Nobility was more reluctant due to the influence of so-called Gustavians (Gustavianerna), supporting the deposed King Gustav IV Adolf and his then-underage son.

In addition, he had demonstrated his interest in a rapprochement between the two countries by refraining from invading Sweden during the Finnish War with Russia.

[3] A monument to Charles August was commissioned by Prince Frederik of Hesse and erected in 1810 in the royal park at Bygdøy near Oslo.

Before his departure from Oslo, a grand farewell party was held in his honour, and a group of wealthy citizens formed the charitable foundation Prinds Christian Augusts Minde.