That distinguished campaigner had assured the commander-in-chief that the reduction of the city would be an easy achievement.

Alexander soon declared that the enterprise was the most difficult one that he had ever undertaken.

Yet, two years before, he had carried to its triumphant conclusion the famous siege of Antwerp.

He stationed his own division upon the isle of Kadzand, and strengthened his camp by additionally fortifying those shadowy bulwarks, by which the island, since the age of Dante, had entrenched itself against the assaults of ocean.
On the other hand, La Motte, by the orders of his chief, had succeeded, after a sharp struggle, in carrying the fort of St.Anne.A still more important step was the surprising of Blankenburg, a small fortified place on the coast, about midway between Ostend and Sluys, by which the sea-communications with the former city for the relief of the beleaguered town were interrupted.
Parma's demonstrations against Sluys had commenced in the early days of June.

The commandant of the place was Arnold de Groenevelt, a Dutch noble of ancient lineage and approved valour.