Conrad IV of Tann  Conrad IV of Tann (), also "of Thann" or "of Dahn", (?-1236) was the 48th Bishop of Speyer, holding office from 1233 to 1236. Conrad came from the von Dahn family who, as episcopal ministeriales, owned estates in the southern Palatinate. The three castles of the Dahn as well as Neudahn Castle were initially all owned by the family. Conrad of Dahn, brother of the castellan, Frederick I of Dahn, was the cathedral canon in Worms, curator ("Domkustos") of St. Cyriakus in Worms-Neuhausen, and provost of the chu