Under the false name of Francis Guyon he made his way to Delft, pretended to be a zealous Calvinist flying from persecution, and went about begging for alms.

The prince, even in his poverty always charitable, hearing of his needy condition sent to the man a present of twelve crowns.

With this gift Gerard bought a pair of pistols and on July 10, 1584, having managed on some pretext to gain admittance to the Prinsenhof, he concealed himself in a dark corner by the stairs just opposite the door of the room where William and his family were dining.

As the prince, accompanied by his wife, three of his daughters and one of his sisters, came out and was approaching the staircase, the assassin darted forward and fired two bullets into his breast.

The wound was mortal; William fell to the ground and speedily expired.