William of Nassau (1601–1627)

He was the illegitimate son of stadholder Maurice of Nassau, Prince of Orange and his mistress Margaretha van Mechelen.

He went by the title Rijksgraaf (Count of the Holy Roman Empire) van LaLecq" and was also popularly known in French as the "Chevalier de Nassau".

On 18 August, not long before the end of the siege, fighting with the French troops at the front, Willem received a bullet wound which later proved fatal.

On 4 April 1627, 4 months before his death, Willem married Anna van der Noot, lady of Hoogwoud and Aartswoud, in Sluis.

Though he had no children with Anna, he had one illegitimate son by Barbara Augustinus Cocx, Willem Jonker van Nassau (1620–1679) .