The Commander determined that the enterprise should be attempted. It was not a novelty, because Mondragon, as we have seen, had already most brilliantly conducted a very similar expedition. The present was, however, a much more daring scheme. The other exploit, although sufficiently hazardous, and entirely, successful, had been a victory gained over the sea alone. It had been a surprise, and had been effected without any opposition from human enemies. Here, however, they were to deal, not only with the ocean and darkness, but with a watchful and determined foe. The Zealanders were aware that the enterprise was in contemplation, and their vessels lay about the contiguous waters in considerable force. Nevertheless, the determination of the Grand Commander was hailed with enthusiasm by his troops. Having satisfied himself by personal experiment that the enterprise was possible, and that therefore his brave soldiers could accomplish it, he decided that the glory of the achievement should be fairly shared, as before, among the different nations which served the King.
After completing his preparations, Requesens came to Tholen, at which rendezvous were assembled three thousand infantry, partly Spaniards, partly Germans, partly Walloons. Besides these, a picked corps of two hundred sappers and miners was to accompany the expedition, in order that no time might be lost in fortifying themselves as soon as they had seized possession of Schouwen. Four hundred mounted troopers were, moreover, stationed in the town of Tholen, while the little fleet, which had been prepared at Antwerp; lay near that city ready to co-operate with the land force as soon as they, should complete their enterprise. The Grand Commander now divided the whole force into two parts: One half was to remain in the boats, under the command of Mondragon; the other half, accompanied by the two hundred pioneers, were to wade through the sea from Philipsland to Duiveland and Schouwen. Each soldier of this detachment was provided with a pair of shoes, two pounds of powder, and rations for three days in a canvas bag suspended at his neck. The leader of this expedition was Don Osorio d’Ulloa, an officer distinguished for his experience and bravery.