Ka cika wannan magana: An yi renon Ernest a matsayin ɗan Calvin a lokacin Yaƙin Shekara Talatin. Ya yi babban rangadinsa zuwa Faransa da Italiya, kuma ya yi yaƙi tare da Hesse-Kassel a cikin shekarun ƙarshe na yaƙin, misali a
Yaƙin Nördlingen a ranar 3 ga Agusta 1645. A cikin 1647, sojojin Landgravine Amalie Elisabeth sun sake cinye Lower Katzenelnbogen kuma sun mayar da shi zuwa Hesse-Kassel. A shekara ta 1649, Ernest ya tsufa kuma ya sami Lower Katzenelnbogen. Wannan ya sanya shi wanda ya kafa layin Hesse-Rheinfels. Hesse-Rheinfels ba a ɗauke shi a matsayin mai mulki ba: ya kasance a ƙarƙashin ikon mallakar Hesse-Kassel, kamar yadda sauran sassan Rotenburg Quarter suka yi. Cikakkun bayanai game da dangantakar da ke tsakanin Hesse-Rheinfels da Hesse-Kassel an tsara su a cikin jerin yarjejeniyoyin gidaje; duk da haka, rikice-rikicen siyasa da shari'a sukan tashi tsakanin gidajen biyu.