As the siege proceeded, and as the hopes of relief died away, great confusion began to reign within the city.  The garrison, originally of a thousand veterans, besides burgher militia, had been much diminished.  Two commandants of the place, one after another, had lost their lives.  On the 1st of June, Governor De Masieres, Captain Mongyn, the father-confessor of the garrison, and two soldiers, being on the top of the great church tower taking observations, were all brought down with one cannon-shot.  Thus the uses of artillery were again proved to be something more than to scare cowards.

The final result seemed to have been brought about almost by accident, if accident could be admitted as a factor in such accurate calculations as those of Maurice.  On the 24th June Captains Haen and Bievry were relieving watch in the trenches near the great north ravelin of the town—­a bulwark which had already been much undermined from below and weakened above.  Being adventurous officers, it occurred to them suddenly to scale the wall of the fort and reconnoitre what was going on in the town.  It was hardly probable that they would come back alive from the expedition, but they nevertheless threw some planks across the ditch, and taking a few soldiers with them, climbed cautiously up.  Somewhat to his own surprise, still more to that of the Spanish sentinels, Bievry in a few minutes found himself within the ravelin.  He was closely followed by Captain Haen, Captain Kalf, and by half a company of soldiers.  The alarm was given.  There was a fierce hand-to-hand struggle.  Sixteen of the bold stormers fell, and nine of the garrison of the fort.  The rest fled into the city.  The governor of the place, Captain Gysant, rushing to the rescue without staying to put on his armour, was killed.  Count Solms, on the other hand, came from the besieging camp into the ravelin to investigate the sudden uproar.  To his profound astonishment he was met there, after a brief interval, by a deputation from the city, asking for terms of surrender.  The envoys had already been for some little time looking in vain for a responsible person with whom to treat.  When Maurice was informed of the propositions he thought it at first a trick; for he had known nothing of the little adventure of the three captains.  Soon afterwards he came into a battery whither the deputies had been brought, and the terms of capitulation were soon agreed upon.

Next day the garrison were allowed to go out with sidearms and personal baggage, and fifty waggons were lent them by the victor to bring their wounded men to Antwerp.

Thus was Gertruydenberg surrendered in the very face of Peter Mansfeld, who only became aware of the fact by the salvos of artillery fired in honour of the triumph, and by the blaze of illumination which broke forth over camp and city.