The expedition was partially successful.  Six hundred landed; beating down all opposition.  But a few Scotch companies held firm, and by hard fighting were able at last to drive the invaders back to their sloops, many of which were sunk in the affray, with all on board.  The rest ignominiously retreated.  Had the enterprise been as well executed as it was safely planned, it would have gone hard with the stadholder and his army.  It is difficult to see in what way he could have extricated himself from such a dilemma, being thus cut off from his supplies and his fleet, and therefore from all possibility of carrying out his design or effecting his escape to Zeeland.  Certainly thus far, fortune had favoured his bold adventure.

He now sent his own trumpeter, Master Hans, to summon Ysendyke to a surrender.  The answer was a bullet which went through the head of unfortunate Master Hans.  Maurice, enraged at this barbarous violation of the laws of war, drew his lines closer.  Next day the garrison, numbering six hundred, mostly Italians, capitulated, and gave up the musketeer who had murdered the trumpeter.

Two days later the army appeared before Aardenburg, a well-fortified town four miles south of Sluys.  It surrendered disgracefully, without striking a blow.  The place was a most important position for the investment of Sluys.  Four or five miles further towards the west, two nearly parallel streams, both navigable, called the Sweet and the Salt, ran from Dam to Sluys.  It was a necessary but most delicate operation, to tie up these two important arteries.  An expedition despatched in this direction came upon Trivulzio with a strong force of cavalry, posted at a pass called Stamper’s Hook, which controlled the first of these streams.  The narrowness of the pathway gave the advantage to the Italian commander.  A warm action took place, in which the republican cavalry were worsted, and Paul Bax severely wounded.  Maurice coming up with the infantry at a moment when the prospect was very black, turned defeat into victory and completely routed the enemy, who fled from the precious position with a loss of five hundred killed and three hundred prisoners, eleven officers among them.  The Sweet was now in the stadholder’s possession.

Next day he marched against the Salt, at a pass where fourteen hundred Spaniards were stationed.  Making very ostentatious preparations for an attack upon this position, he suddenly fell backwards down the stream to a point which he had discovered to be fordable at low water, and marched his whole army through the stream while the skirmishing was going on a few miles farther up.  The Spaniards, discovering their error, and fearing to be cut off, scampered hastily away to Dam.  Both streams were now in the control of the republican army, while the single fort of St. Joris was all that was now interposed between Maurice and the much-coveted Swint.  This redoubt, armed with nine guns, and provided with a competent, garrison, was surrendered on the 23rd May.