Oldenburg (shaded gray), within the Holy Germanian Empire.

The Grand Duchy of Oldenburg is an consistutent state of the Holy Germanian Empire, named for it's capital, Oldenburg. Oldenburg has existed from 1180-present as a county, duchy, and grand duchy. Its ruling family is the House of Oldenburg, who also occupy the Danish throne and once were on the Sweedish and Youngovakian thrones.