But at last the allies determined to make a systematic assault on the enemy with their combined force, and to put an end to the siege by a grand attack as well on the dam as on the bridge. The 16th of May, 1585, was fixed upon for the execution of this design, and both armies used their utmost endeavors to make this day decisive. The force of the Hollanders and Zealanders, united to that of Antwerp, exceeded two hundred ships, to man which they had stripped their towns and citadels, and with this force they purposed to attack the Cowenstein dam on both sides. The bridge over the Scheldt was to be assailed with new machines of Gianibelli's invention, and the Duke of Parma thereby hindered from assisting the defence of the dam. Alexander, apprised of the danger which threatened him, spared nothing on his side to meet it with energy. Immediately after getting possession of the dam he had caused redoubts to be erected at five different, places, and had given the command of them to the most experienced officers of the army. The first of these, which was called the Cross battery, was erected on the spot where the Cowenstein darn enters the great embankment of the Scheldt, and makes with the latter the form of a cross; the Spaniard, Mondragone, was appointed to the command of this battery. A thousand paces farther on, near the castle of Cowenstein, was posted the battery of St. James, which was entrusted to the command of Camillo di Monte. At an equal distance from this lay the battery of St. George, and at a thousand paces from the latter, the Pile battery, under the command of Gamboa, so called from the pile-work on which it rested; at the farthest end of the darn, near Stabroek, was the fifth redoubt, where Count Mansfeld, with Capizuechi, an Italian, commanded. All these forts the prince now strengthened with artillery and men; on both sides of the dam, and along its whole extent, he caused piles to be driven, as well to render the main embankment firmer, as to impede the labor of the pioneers, who were to dig through it.