On the following day, Prince Maurice, making a reconnoissance of the works with his usual calmness, yet with the habitual contempt of personal danger which made so singular a contrast with the cautious and painstaking characteristics of his strategy, very narrowly escaped death.  A shot from the fort struck so hard upon the buckler under cover of which he was taking his observations as to fell him to the ground.  Sir Francis Vere, who was with the prince under the same buckler, likewise measured his length in the trench, but both escaped serious injury.

Pauli, one of the States commissioners present in the camp, wrote to Barneveld that it was to be hoped that the accident might prove a warning to his Excellency.  He had repeatedly remonstrated with him, he said, against his reckless exposure of himself to unnecessary danger, but he was so energetic and so full of courage that it was impossible to restrain him from being everywhere every day.

Three days later, the letter Y did its work.  At ten o’clock 15 July, of the night of the 15th July, Prince Maurice ordered the mines to be sprung, when the north ravelin was blown into the air, and some forty of the garrison with it.  Two of them came flying into the besiegers’ camp, and, strange to say, one was alive and sound.  The catastrophe finished the sixty-five days’ siege, the breach was no longer defensible, the obstinacy of the burghers was exhausted, and capitulation followed.  In truth, there had been a subterranean intrigue going on for many weeks, which was almost as effective as the mine.  A certain Jan to Boer had been going back and forth between camp and city, under various pretexts and safe-conducts, and it had at last appeared that the Jesuits and the five hundred of Verdugo’s veterans were all that prevented Groningen from returning to the Union.  There had been severe fighting within the city itself, for the Jesuits had procured the transfer of the veterans from the faubourg to the town itself, and the result of all these operations, political, military, and jesuitical, was that on 22nd July articles of surrender were finally agreed upon between Maurice and a deputation from the magistrates, the guilds, and commander Lanckema.

The city was to take its place thenceforth as a member of the Union.  William Lewis, already stadholder of Friesland for the united States, was to be recognised as chief magistrate of the whole province, which was thus to retain all its ancient privileges, laws, and rights of self-government, while it exchanged its dependence on a distant, foreign, and decaying despotism for incorporation with a young and vigorous commonwealth.

It was arranged that no religion but the reformed religion, as then practised in the united republic, should be publicly exercised in the province, but that no man should be questioned as to his faith, or troubled in his conscience:  Cloisters and ecclesiastical property were to remain ‘in statu quo,’ until the States-General should come to a definite conclusion on these subjects.