It would likewise have been more judicious, according to the lamentations of Justus Lipsius, had the necessity of saving Sluys been thought of in time. Now that it was thoroughly enclosed, so that a mouse could scarce creep through the lines, the archduke was feverish to send in a thousand wagon loads of provisions. Spinola, although in reality commander-in-chief of a Spanish army, and not strictly subject to the orders of the Flemish sovereigns, obeyed the appeal of the archduke, but he obeyed most reluctantly. Two-thirds of Ostend had been effaced, and it was hard to turn even for a moment from the spot until all should have been destroyed.
Leaving Rivas and Bucquoy to guard the entrenchments, and to keep steadily to the work, Spinola took the field with a large force of all arms, including the late mutineers and the troops of Count Trivulzio. On the 8th August he appeared in the neighbourhood of the Salt and Sweet streams, and exchanged a few cannon-shots with the republicans. Next day he made a desperate assault with three thousand men and some companies of cavalry, upon Lewis William's quarters, where he had reason to believe the lines were weakest. He received from that most vigilant commander a hearty welcome, however, and after a long skirmish was obliged to withdraw, carrying off his dead and wounded, together with a few cart-horses which had been found grazing outside the trenches. Not satisfied with these trophies or such results, he remained several days inactive, and then suddenly whirled around Aardenburg with his whole army, directly southward of Sluys, seized the forts of St. Catharine and St. Philip, which had been left with very small garrisons, and then made a furious attempt to break the lines at Oostburg, hoping to cross the fords at that place, and thus push his way into the isle of Cadzand. The resistance to his progress was obstinate, the result for a time doubtful. After severe fighting however he crossed the waters of Oostburg in the face of the enemy. Maurice meantime had collected all his strength at the vital position of Cadzand, hoping to deal, or at least to parry, a mortal blow.
On the 17th, on Cadzand dyke, between two redoubts, Spinola again met Lewis William, who had been transferred to that important position. A severe struggle ensued. The Spaniards were in superior force, and Lewis William, commanding the advance only of the States troops, was hard pressed. Moving always in the thickest of the fight, he would probably have that day laid down his life, as so many of his race had done before in the cause of the republic, had not Colonel van Dorp come to his rescue, and so laid about him with a great broad sword, that the dyke was kept until Maurice arrived with Eytzinga's Frisian regiment and other reserves. Van Dorp then fell covered with wounds. Here was the decisive combat. The two commanders-in-chief met face to face for the first time, and could Spinola have gained the position of Cadzand the fate of Maurice must have been sealed. But all his efforts were vain. The stadholder, by coolness and promptness, saved the day, and inflicted a bloody repulse upon the Catholics. Spinola had displayed excellent generalship, but it is not surprising that the young volunteer should have failed upon his first great field day to defeat Maurice of Nassau and his cousin Lewis William. He withdrew discomfited at last, leaving several hundred dead upon the field, definitely renouncing all hope of relieving Sluys, and retiring by way of Dam to his camp before Ostend. Next day the town capitulated.
The garrison were allowed to depart with the honours of war, and the same terms were accorded to the inhabitants, both in secular and religious matters, as were usual when Maurice re-occupied any portion of the republic. Between three and four thousand creatures, looking rather like ghosts from the churchyards than living soldiers, marched out, with drums beating, colours displayed, matches lighted, and bullet in mouth. Sixty of them fell dead before the dismal procession had passed out of the gates. Besides these troops were nearly fifteen hundred galley-slaves, even more like shadows than the rest, as they had been regularly sent forth during the latter days of the siege to browse upon soutenelle in the submerged meadows, or to drown or starve if unable to find a sufficient supply of that weed. These unfortunate victims of Mahometan and Christian tyranny were nearly all Turks, and by the care of the Dutch Government were sent back by sea to their homes. A few of them entered the service of the States.
The evacuation of Sluys by Governor Serrano and his garrison was upon the 20th August. Next day the stadholder took possession, bestowing the nominal government of the place upon his brother Frederic Henry. The atmosphere, naturally enough, was pestiferous, and young Count Lewis Gunther of Nassau, who had so brilliantly led the cavalry on the famous day of Nieuport, died of fever soon after entering the town infinitely regretted by every one who wished well to the republic.
Thus an important portion of Zeeland was restored, to its natural owners. A seaport which in those days was an excellent one, and more than a compensation for the isolated fishing village already beleaguered for upwards of three years, had been captured in three months. The States-General congratulated their stadholder on such prompt and efficient work, while the garrison of Ostend, first learning the authentic news seven days afterwards, although at a distance of only fourteen miles, had cause to go upon their knees and sing praises to the Most High.
The question now arose as to the relief of Ostend. Maurice was decidedly opposed to any such scheme. He had got a better Ostend in Slays, and he saw no motive for spending money and blood in any further attempt to gain possession of a ruin, which, even if conquered, could only with extreme difficulty be held. The States were of a diametrically opposite opinion. They insisted that the stadholder, so soon he could complete his preparations, should march straight upon Spinola's works and break up the siege, even at the risk of a general action. They were willing once more to take the terrible chance of a defeat in Flanders. Maurice, with a heavy heart, bowed to their decision, showing by his conduct the very spirit of a republican soldier, obeying the civil magistrate, even when that obedience was like to bring disaster upon the commonwealth. But much was to be done before he could undertake this new adventure.
Meantime the garrison in Ostend were at their last gasp. On being asked by the States-General whether it was possible to hold out for twenty days longer, Marquette called a council of officers, who decided that they would do their best, but that it was impossible to fix a day or hour when resistance must cease. Obviously, however, the siege was in its extreme old age. The inevitable end was approaching.
Before the middle of September the enemy was thoroughly established in possession of the new Hell's Mouth, the new Porcupine, and all the other bastions of the new entrenchment. On the 13th of that month the last supreme effort was made, and the Sand Hill, that all-important redoubt, which during these three dismal years had triumphantly resisted every assault, was at last carried by storm. The enemy had now gained possession of the whole town except Little Troy. The new harbour would be theirs in a few hours, and as for Troy itself, those hastily and flimsily constructed ramparts were not likely to justify the vaunts uttered when they were thrown up nor to hold out many minutes before the whole artillery of Spinola. Plainly on this last morsel of the fatal sandbank the word surrender must be spoken, unless the advancing trumpets of Maurice should now be heard. But there was no such welcome sound in the air. The weather was so persistently rainy and stormy that the roads became impassable, and Maurice, although ready and intending to march towards Spinola to offer him battle, was unable for some days to move. Meantime a council, summoned by Marquette, of all the officers, decided that Ostend must be abandoned now that Ostend had ceased to exist.
On the 20th September the Accord was signed with Spinola. The garrison were to march out with their arms. They were to carry off four cannon but no powder. All clerical persons were to leave the place, with their goods and chattels. All prisoners taken on both sides during the siege were to be released. Burghers, sutlers, and others, to go whither they would, undisturbed. And thus the archdukes, after three years and seventy-seven days of siege, obtained their prize. Three thousand men, in good health, marched out of little Troy with the honours of war. The officers were entertained by Spinola and his comrades at a magnificent banquet, in recognition of the unexampled heroism with which the town had been defended. Subsequently the whole force marched to the headquarters of the States' army in and about Sluys. They were received by Prince Maurice, who stood bareheaded and surrounded by his most distinguished officers; to greet them and to shake them warmly by the hand. Surely no defeated garrison ever deserved more respect from friend or foe.