Principality of Isenburg

The Principality of Isenburg was a small German state that existed from 1806 to 1815 in what is now south-eastern Hesse. It was formed when the prince of Isenburg and Büdingen in Birstein and the counts of the Ysenburg lines at Büdingen, Meerholz and Wächtersbach placed their imperial territories under the protection of Napoleon's Confederation of the Rhine. The principality was split into two parts: a southern block around Offenbach, Neu-Isenburg and Dreieich, and a northern block around Birstein, Büdingen and Wächtersbach, separated by the Principality of Hanau. It covered about 790 square kilometres and contained four small towns and dozens of villages; Offenbach, the largest settlement, served as the princely residence. Isenburg contributed troops to Napoleon's campaigns, including the Peninsular War. After the collapse of the Confederation of the Rhine, the Congress of Vienna assigned the territory to Austria in June 1815, and Austria soon ceded it to the Grand Duke of Hesse, who partitioned it with Hesse-Kassel.