In the 17th century the castle was rebuilt in the style of the Renaissance, but later destroyed and now only the cellars of this construction remain. In the 18th century Prince Wilhelm Heinrich had his architect Stengel build a new Baroque residence on the same site. Since then the castle has suffered various bouts of destruction and was partially burnt down and reconstructed before being thoroughly and magnificently renovated in 1989.
http://www.saarbruecken.de/en/tourism/saarbruecken/sights/saarbruecken_castle