Nassau

Nassau was a German duchy named for the castle on the Lahn. In 1337 the lands of the House of Nassau were divided among branches descended from the partition of 1255.

In 1806 Napoleon pressed Nassau-Usingen and Nassau-Weilburg to form the duchy, which abolished serfdom that year. It joined the coalition against Napoleon in 1813, adopted a constitution in 1814 and entered the German Confederation in 1815. William of Nassau-Weilburg inherited the whole duchy in 1816, making Wiesbaden its sole capital.