Isenburg-Grenzau

Isenburg-Grenzau was the name of several states of the Holy Roman Empire, seated in the Lordship of Grenzau, in modern Rhineland-Palatinate, Germany.

In 1213 Henry I began the construction of Castle Grenzau, located on a mountain spur along the Rhine trade route from Leipzig to Flanders.

In 1286 Henry II partitioned his territories between his sons, into the states of Isenburg-Grenzau (to Eberhard I), Isenburg-Cleberg (to Louis) and Isenburg-Arnfels (to Gerlach).

Gerlach's fame and respect, and by extension that of the House of Isenburg, had increased dramatically when he held the Emperor's banner at the Reichstag at Worms in 1495.

Isenburg-Grenzau was made an Imperial Estate of the Holy Roman Empire with a seat in the Bench of Counts of the Wetterau.

Ernest was, inter alia, a field captain of the Imperial army during the Thirty Years' War, fighting predominantly in the Netherlands.

After Ernst's death in Brussels in 1664 at age 80 and without direct heirs, his territories were reclaimed as feudal tenures by the Archbishoprics of Cologne, Trier and Fulda.