Nassau is a town located in the German state of Rhineland-Palatinate. It lies on the lower course of the Lahn River, on the mouth of the Mühlbach, between Limburg an der Lahn and the spa town of Bad Ems, and is located in the Nassau Nature Park, surrounded by the Westerwald to the north and the Taunus to the south. The town is on the German-Dutch holiday road, the Orange Route. As of 2021, it had a population of 4,592.

Adolf was the count of Nassau from about 1276 and the elected king of Germany from 1292 until his deposition by the prince-electors in 1298. He was never crowned by the pope, which would have secured him the imperial title. He was the first physically and mentally healthy ruler of the Holy Roman Empire ever to be deposed without a papal excommunication. Adolf died shortly afterwards in the Battle of Göllheim fighting against his successor Albert of Habsburg.