 According to this treaty, the rule over the Principality of Lüneburg would alternate between the two families.However, the dispute continued; together with his brothers, Frederick eventually won the war by conquering Lüneburg itself in 1388.In May 1400, Frederick took part in an assembly of the Princes of the Holy Roman Empire in Frankfurt; the purpose of the meeting was to discuss the deposition of the incapable king Wenceslaus.