The Order of Leopold is one of the three current Belgian national honorary orders of knighthood. It is the oldest and highest order of Belgium and is named in honour of its founder, King Leopold I. It consists of a military, a maritime and a civil division. The maritime division is only awarded to personnel of the merchant navy, and the military division to military personnel. The decoration was established on 11 July 1832 and is awarded by Royal decree.

Karl Anton, Prince of Hohenzollern-Sigmaringen was the last prince of Hohenzollern-Sigmaringen before the territory was annexed by the Kingdom of Prussia in 1849. Afterwards he continued to be titular prince of his house and, with the death of the last prince of Hohenzollern-Hechingen in 1869, of the entire House of Hohenzollern. He served as Minister President of Prussia from 1858 to 1862, the only Hohenzollern prince to hold the post. His second son, Karl, became king of Romania. The offer of the throne of Spain to his eldest son, Leopold, was one of the causes of the Franco-Prussian War, which led to the unification of Germany and the creation of the German Empire.