A hundred pieces of artillery on the batteries played incessantly on the town, while a blockading squadron of Zeeland ships assisted in the bombardment, and so terrible was the fire, that when the town was finally taken only four houses were found to have escaped injury. Two commandants of the place were killed one after the other, and the garrison of a thousand veterans, besides the burgher militia, was greatly reduced in strength. At last, after ninety days' siege, the town suddenly fell. Upon the 24th of June three Dutch captains were relieving guard in the trenches near the great north bastion of the town, when it occurred to them to scale the wall of the fort and see what was going on inside. They threw some planks across the ditch, and taking half a company of soldiers, climbed cautiously up. They obtained a foothold before the alarm was given. There was a fierce hand to hand struggle, and sixteen of the party fell, and nine of the garrison. The rest fled into the city. The Governor Gysant, rushing to the rescue without staying to put on his armour, was killed. Count Solms came from the besieging camp to investigate the sudden uproar, and to his profound astonishment was met by a deputation from the city asking for terms of surrender. Prince Maurice soon afterwards came up, and the terms of capitulation were agreed upon. The garrison were allowed to retire with side arms and baggage, and fifty wagons were lent to them to carry off their wounded. In the following spring Coevorden, which had been invested by Verdugo, was relieved, and Groningen, the last great city of the Netherlands in the hands of the Spaniards, was besieged. Mines were driven under its principal bastion, and when these were sprung, after sixty-five days' siege, the city was forced to surrender. Thus for the first time, after years of warfare, Holland, Zeeland, and Friesland became truly united, and free from the grasp of the hated invader. Throughout the last three years of warfare Sir Francis Vere had proved an able assistant to the prince, and the English troops had fought bravely side by side with the Dutch; but their contingent had been but a small one, for the majority of Vere's force had, like that of the Spaniards, been withdrawn for service in France. The struggle in that country was nearly at an end. The conversion of Henry of Navarre for the second time to the Catholic religion had ranged many Catholics, who had hitherto been opposed to him, under his banner, while many had fallen away from the ranks of the League in disgust, when Philip of Spain at last threw off the mask of disinterestedness, and proposed his nephew the Archduke Ernest as king of France.