Historians assume that a previous building was already erected in the 10th century. The ruin, located near the Rheinsteig trail, served as a depository for the Imperial Regalia. These regalia of the Holy Roman Empire - among other things, the Crown, Imperial Orb and Holy Lance - were finally transferred to Trifels Castle in 1125. Furthermore, Hammerstein Castle is the showplace of the legend of the historically founded the marriage between Otto I and Irmingard of Verdun: as Otto and Irmingrad were related to each by fourth degree, an objection to the marriage was raised through pressure by Erkanbald, the Archbishop of Mainz - following which the couple was excommunicated in Nijmegen in 1018.