 After only slightly over a year ruling his family's small principality, Karl Anton abdicated in December 1849 in favor of his distant cousin, the King of Prussia, and Hohenzollern-Sigmaringen, along with the neighboring principality of Hohenzollern-Hechingen, was annexed by Prussia.After his abdication, Karl Anton became a prominent figure in Prussian politics.After the fall of the reactionary Manteuffel ministry in 1858, and the accession of Prince William as regent for his incapacitated brother, King Frederick William IV, a new, moderately liberal ministry was appointed, with Karl Anton as Minister-President.