The Château des Tours was built in the 14th century. At that time it had three towers: one had a polygonal interior and was the dungeon, and the others were circular flanking an oblong building on the east and west corners of its south face; then, at the same corners on the north face, there are sentry boxes with Corbels. The oldest part is in the south of the present castle and is also a little higher.
North of the original castle there was a courtyard formed by the castle and crenellated walls outside with wide and deep ditches below. These ditches remain but the walls were replaced in the 16th century by rectangular buildings. At the east and west corners of the north facade there are two round towers, less high than the others, but topped like them with machicolations. There is a door between these two towers above which are the Arms of Calvimont carved on a large stone: they have lain since 1793 a few steps in front of the door.
The castle was restored by Viollet-le-Duc in the 19th century.
References:The Château du Haut-Koenigsbourg is situated in a strategic area on a rocky spur overlooking the Upper Rhine Plain, it was used by successive powers from the Middle Ages until the Thirty Years' War when it was abandoned. From 1900 to 1908 it was rebuilt at the behest of the German kaiser Wilhelm II. Today it is a major tourist site, attracting more than 500,000 visitors a year.
The first records of a castle built by the Hohenstaufens date back to 1147. The fortress changed its name to Koenigsburg (royal castle) around 1157. The castle was handed over to the Tiersteins by the Habsburgs following its destruction in 1462. They rebuilt and enlarged it, installing a defensive system designed to withstand artillery fire.
The fortification work accomplished over the 15th century did not suffice to keep the Swedish artillery at bay during the Thirty Years War, and the defences were overrun.