The failure of his attempt upon the fort of Lillo compelled the Prince of Parma to change his measures. As he could not succeed in stopping the passage of the Scheldt by his original plan, on which the success of the siege entirely depended, he determined to effect his purpose by throwing a bridge across the whole breadth of the river. The thought was bold, and there were many who held it to be rash. Both the breadth of the stream, which at this part exceeds twelve hundred paces, as well as its violence, which is still further augmented by the tides of the neighboring sea, appeared to render every attempt of this kind impracticable. Moreover, he had to contend with a deficiency of timber, vessels, and workmen, as well as with the dangerous position between the fleets of Antwerp and of Zealand, to which it would necessarily be an easy task, in combination with a boisterous element, to interrupt so tedious a work. But the Prince of Parma knew his power, and his settled resolution would yield to nothing short of absolute impossibility. After he had caused the breadth as well as the depth of the river to be measured, and had consulted with two of his most skilful engineers, Barocci and Plato, it was settled that the bridge should be constructed between Calloo in Flanders and Ordain in Brabant. This spot was selected because the river is here narrowest, and bends a little to the right, and so detains vessels a while by compelling them to tack. To cover the bridge strong bastions were erected at both ends, of which the one on the Flanders side was named Fort St. Maria, the other, on the Brabant side, Fort St. Philip, in honor of the king.