There were many grand attacks made by the English on St. Malo, during the siege; for they had full four hundred cannon, which fired day and night against the town and castle. The governor, whose name was Morfonace, a valiant man at arms, was resolved to defend it well, aided by the councils of sir Hervé de Malatrait, the lord de Comber and the viscount de la Belliere, and had so far succeeded that there was not as yet any apparent damage. In the adjacent country, as I have before said, was the flower of France, as well great lords as others; they amounted to sixteen thousand men at arms, knights and squires, with upwards of one hundred thousand horses. They were as willing for the combat as the English could be; but each of them fought to have an advantage: what, however, prevented this from happening several times was the large river, when the tide was in, between the two armies, which hindered them from attacking each other. The mine was advancing, of which the inhabitants of St. Malo had some suspicions. In such large armies as these, it was not possible but that the foragers of each should frequently have rencounters, in which fortune favoured sometimes one party, and sometimes the other; for there were very expert and youthful knights of each army who sought for such exploits. The miners of the duke of Lancaster laboured hard at their work day and night, to carry it under the town and throw down part of the walls, so that the men at arms and archers might easily gain an entrance.
Moronace and the knights in the town guessed what they were about, and knew well that if they should succeed they were ruined. They did not fear their other assaults, for the town was well provided with all sorts of stores and artillery for two years, if necessary: wherefore they considered how they might best counteract this mine. After having long consulted, they succeeded in their attempt: it was in some sort accidental, for things fell out with extraordinary good fortune for them.
Richard, earl of Arundel, was on guard one night with his people, but he was very inattentive to obey the orders he had received, of which the garrison was informed by heir spies or otherwise. When they had fixed on an hour in which they imagined the army (trusting to lord Arundel’s want of vigilance) would be fast asleep, they sallied from the town very secretly, and advanced to where the miners were at work, who had little more to do to complete their mine. Morfonace and his company, being prepared to accomplish their enterprise, destroyed the mine at their ease; and some of the workman who were within were never seen afterwards, as the mine fell upon them.
When they had finished this business, they said they would awaken the guard next the town, in order that they might know with what success their gallantry had been crowned. They advanced to one of the wings of the army, shouting their war-cry, cutting down tents, and slaying all they met, so that the whole army was seriously alarmed. Morfonace and his companions retreated into St. Malo without any loss; during which time the English armed themselves, and advanced in front of the duke’s division, who was much astonished at this event: he demanded how it could have happened, when they informed him, that by the negligence of the guard, the mine had been destroyed, and they had suffered a great loss. Upon this, the earl of Arundel was sent for and sharply reprimanded by the duke of Lancaster and earl of Cambridge for his neglect: he excused himself as well as he was able, but was so greatly ashamed that he had rather have lost several thousand pounds. After the destruction of the mine, the principal chiefs held a council to determine how they should act. They saw they had lost the season of the year, which was not to be regained; for should they attempt another mine, winter would come before it could be finished; they therefore resolved, taking all things into consideration, that their wisest plan would be to break up their camp and return to England. Orders were, in consequence, issued by the duke and the marshals for the army to decamp, and embark on board their fleet in the port of St. Malo. This order was soon obeyed; and, having a favourable wind, they made sail for Southampton, where they arrived. On disembarking, they learnt that sir John Arundel, the governor of Southampton, was gone to reinforce the garrison of Cherbourg.