Principality of Heitersheim

[1] In 1428, Heitersheim, which had by then obtained imperial immediacy, became the temporary seat of the Grand Prior of Germany, the top Hospitaller official in the German kingdom.

In 1548, as a reward for the knights' service in the wars against the Turks, Emperor Charles V granted it princely rank and admitted it to the Imperial Diet "with seat and vote" (mit Sitz und Stimme).

[2] In the 18th century Heitersheim fell gradually under the domination of the Habsburgs, who were prepared to grant it along with the rest of the Breisgau to Duke Ercole III of Modena in the Treaty of Campo Formio (1797).

[1] In 1803, however, it was one of only three ecclesiastical principalities to survive the territorial reorganization brought about by the Reichsdeputationshauptschluss in accordance with the Treaty of Lunéville (1801) that ended the War of the Second Coalition.

As part of the settlement of the war, Duke Ercole received the rest of the Breisgau[3] and the Principality of Heitersheim annexed the neighbouring county of Bonndorf, thus greatly expanding in size.