The castle suffered heavily in the Dutch Spanish war as it wasn't built to withstand the new heavy duty cannons and mortars.

The Spanish armies severely crippled the defensive walls of Valkenburg and left the castle in a far state of disrepair with its magnificent towers now collapsed and its roofs burned to ashes.

The Dutch armies attempted to repair the castle but were unsuccessful due to the ongoing wars with the Spaniards and the French.

[1] The castle was slighted during the Franco-Dutch War, in 1672, by the army of Stadtholder Willem III (the later King of England) to prevent it falling into French hands.

Excavation of the site has revealed various rebuild periods through the centuries that can be tracked by color and materials changes in the structure.