At the end of the 15th century, Jean de La Marck added a low courtyard to the castle, surrounded by walls 4.5 metres thick. The citadel then covered 15,000 square metres. From 1530, a new wall was built encroaching on the interior of the lower courtyard. Between the two walls, thousands of tons of stone and mud were piled up. The curtain walls were thus increased to 26 metres in thickness! The top of the terraces thus created is at the same level as the reliefs that dominate the castle. Dwellings equipped with latrines were built for the troops in this filling.