Wilhelm II, anxious to underline the fact that Alsace was German territory once more, saw the castle as a symbolic marker for the western limit of his empire. He decided to undertake a complete restoration of the castle.
The architect Bodo Ebhardt was entrusted with the restoration project. His approach was one of rigorous scientific principles, considering the level of knowledge at the time: He listed all the archaeological remains found on the site, studied archive documents, analysed the architecture… and when in doubt, referred to examples chosen among structures built around the same time.
The restoration work was carried out from 1900 to 1908.