When Rudolf died on Oct 15, 1080, in Merseburg, his territories had been inherited by Berthold II of Zähringen.even so the town went to his son Otto and his family the von Wetter's. Berhold's next son, Conrad, awarded industry rights to town, which makes it the oldest Zähringerstadt in Switzerland https://zahnarztpraxis87531.blog5star.com/421338/rheinfelden-secrets