Property of the Crown (1604–1797)

Having died in debt in 1604, Mansfeld had to bequeath his property (including collections of paintings and sculptures) to King Philip III of Spain. However, as the Governor's successors did not regularly reside in Luxembourg, the Spanish Crown barely looked after "la casa y fontana real" ("the house and royal fountain"). The gardens were laid to waste and part of the buildings fell into disrepair. Meanwhile, the brasserie and baths were rented out to private individuals.

During the siege of the Fortress of Luxembourg by Louis XIV between 1683 and 1684, the remaining buildings sustained heavy bomb damage, which completely destroyed what was left of the castle. From left to right, the drawing below shows the cryptoporticus with the old castle at the bottom, the living quarters, the grand gallery and the main entrance building.

The map shows that the land administrators allowed several houses to be built where the former castle buildings once stood. The land was cultivated and a new gardener's house was built.