 John's nephew, Louis de Luxembourg, Count of Saint-Pol and constable to Louis XI in 1465, constructed a monumental keep in 1441.This massive tower (the "tour du connétable" - constable's tower) was 33 m (~108 ft) in diameter and 33 m (~108 ft) high and had walls 11 m (~36 ft) thick.The Château de Ham was besieged several times, notably by Philip II of Spain in 1557.