The Spaniards and Imperialists, finding that the stadholder's lines could not be forced, instituted a blockade, so that the besiegers were themselves besieged.

But Frederick Henry had laid up such ample stores of munitions and provisions that he paid no heed to the cutting of his communications, and pushed on his approaches with the utmost rapidity.

All difficulties were overcome by the engineering skill of the scientific commander; and finally two tunnels sixty feet deep were driven under the broad dry moat before the town walls.

The English regiments during these operations bore the brunt of the fighting and lost heavily, Colonels Harwood and the Earl of Oxford being killed and Colonel Morgan dangerously wounded.

After exploding a mine, a forlorn hope of fifty English troops rushed out from one of the tunnels and made good their footing upon the ramparts.