Either Lütold V von Regensberg or his son Ulrich (+ 1280) has established the fortified town of (Neu)-Regensberg, but when Lütold V died about 1250, his two sons Lütold VI and Ulrich divided the inheritance.
On 9 September 1540 the town, but not the castle, was destroyed by fire, because it was separated from the Oberstadt by a ditch.