In 1352 the French strove to carry on the Breton war on a grander scale, and a large army, commanded by Guy of Nesle, marshal of France, was sent to reinforce the partisans of Charles of Blois.  They met Bentley at Mauron, a few miles north of Ploermel, where one of the most interesting battles of the war was fought Taught by the lesson of Crecy, Nesle had already, in obscure fights in Poitou, ordered the French knights and men-at-arms to fight on foot.[1] He here adopted the same plan for the first time in a battle of importance, but, after a severe struggle, Bentley won the day.  In 1353 Edward III. made a treaty with his captive, Charles of Blois.  In return for a huge ransom Charles was to obtain his liberty, be recognised as Duke of Brittany, marry one of Edward’s daughters, and promise to remain neutral in the Anglo-French struggle.  The treaty involved too great a dislocation of policy to be carried out.  Charles, after visiting Brittany, renounced the compact and returned to his London prison.  Thus the weary war of partisans still went on, and thenceforth the fortunes of Charles depended less upon negotiations than on the growing successes of Bertrand du Guesclin.

    [1] See my paper on Some Neglected Fights between Crecy and
    Poitiers in Engl.  Hist.  Review, vol. xxi., Oct., 1905.

During these years Calais was the centre of much fighting.  Eager to win back the town, the French bribed an Italian mercenary, then in Edward’s service, to admit them into the castle.  The plot was discovered, and Edward and the Prince of Wales crossed over in disguise to help in frustrating the French assault.  The French were enticed into Calais and taken as in a trap.  Edward then sallied out of the town, and rashly engaged in personal encounter with a more numerous enemy.  He was unexpectedly successful, and made wonderful display of his prowess as a knight.  In revenge, the English devastated the neighbouring country by raids like that led by the Duke of Lancaster in 1351, which spread desolation from Therouanne to Etaples.  Of more enduring importance were the gradual extensions of the English pale by the piecemeal conquest of the fortresses of the neighbourhood.  The chief step in this direction was the capture of Guines in 1352.  An archer named John Dancaster, who escaped from French custody in Guines, led his comrades to the assault of the town by a way which he learnt during his imprisonment.  The attack succeeded, and Dancaster, to avoid involving his master in a formal breach of the truce, professed to hold the town on his own account and to be willing to sell it to the highest bidder.  Of course the highest bidder was Edward III. himself, and thus Guines became the southern outpost of the Calais march.

In Aquitaine and Languedoc there was no thought of repose.  In 1349 Lancaster led a foray to the gates of Toulouse, which wrought immense damage but led to no permanent results.  There was incessant border warfare.  The Anglo-Gascon forces spread beyond the limits of Edward’s duchy and captured outposts in Poitou, Perigord, Quercy, and the Agenais.  In retaliation, the Count of Armagnac, a strong upholder of the French cause, did what mischief he could in those parts of Gascony adjacent to his own territories.  On the whole the result of these struggles was a considerable extension of the English power.