The three principal bastions were named the Schottenburg, Moses' Table, and the Flamenburg, the last named defending the entrance to the Geule on the eastern side. There was a strong wall with three bastions, the North Bulwark, the East Bulwark or Pekell, and the Spanish Bulwark at the southeast angle, with an outwork called the Spanish Half Moon on the other side of the Geule. The south side was similarly defended by a wall with four strong bastions, while beyond these at the southwest corner lay a field called the Polder, extending to the point where the Yper Leer ran into the ditches. Sir Francis Vere's first step after his arrival was to throw up three redoubts to strengthen the wall round this field, as had the enemy taken possession of it they might have set the windmills upon it to work and have drained out many of the ditches. Having secured this point he cut a passage to the sea between the Northwest Bulwark and the Flamenburg Fort, so that shipping might enter the port without having to ascend the Geule, exposed to the fire of the Spanish guns. To annoy the enemy and draw them away from the vital point near the sea, he then stationed 200 men on some rising ground surrounded by swamps and ditches at some distance to the south of the city, and from here they were able to open fire on the enemy's boats coming with supplies from Bruges. The operation was successful. The Spaniards, finding their line of communication threatened, advanced in force from their position by the sea, and their forts opened a heavy fire on the little work thrown up. Other similar attempts would have been made to harass the Spaniards and divert them from their main work, had not Sir Francis Vere been severely wounded in the head on the 4th of August by a shot from the Spanish batteries, which continued to keep up a tremendous fire upon the town. So serious was the wound that the surgeons were of opinion that the only chance of saving his life was to send him away from the din and turmoil of the siege; and on the 10th he was taken to Middelburg, where he remained for a month, returning to Ostend long before his wound was properly healed. On the 1st of August a batch of recruits had arrived from England, and on the 8th 1200 more were landed. The fire of the besiegers was now so heavy that the soldiers were forced to dig underground quarters to shelter themselves. Sir Horace Vere led out several sorties; but the besiegers, no longer distracted by the feints contrived by Sir Horace Vere, succeeded in erecting a battery on the margin of the Old Haven, and opened fire on the Sand Hill Fort.