"According to Cuvelier, the boy's mother was so repelled by his looks that she treated him with a coldness that provoked resentment expressed in savage outbursts against parents, siblings, and the world. What is well established by other sources is that as a grown man Du guesclin was the reverse of handsome, and at least in his younger manhood, subject to fits of furious anger.
Bertrand is described at this stage (adolescence) as of middle height (probably not much over five feet), with swarthy complexion, a flat nose, grey eyes, broad shoulders, long arms, and small hands.
The city's defence was commanded by a knight and an ex-peasant. The knight, Bertrand de St. Perm, was Du Guesclin's godfather; the former peasant, Penhouet, a self-made captain experienced in the ruses of warfare. He frustrated an enemy mining project by placing on the walls copper basins containing lead balls whose rattling pinpointed the excavation below and guided a successful countermine. When the Duke of Lancaster caused a herd of pigs to be driven past the gate as a temptation to the hungry town to surrender, Penhouet had a squealing sow led out as the drawbridge was lowered. The hogs stampeded over the bridge, which was promptly raised after them.
Du Guesclin joined a small relief force gathering at Dinan, northeast of Rennes. He was watching companions playing a game of tennis when he received word that his younger brother, Olivier, had been treacherously made prisoner during a truce. Flying into a fury, he rode the forty kilometres to Lancaster's camp, breaking in on a chess game the duke was playing with Sir John Chandos. The duke sent for Thomas of Canterbury, the English knight who had taken the prisoner. Canterbury demanded trial of the charge by judicial combat, to which Du guesclin readily acceded. Before a large assemblage of both armies the two champions fought on horseback, with sword and dagger. Canterbury sought to ride him down, and Du Guesclin stabbed the Englishman's horse, causing it to collapse, pinning its rider. Du Guesclin had to be dragged off his adversary, for whom Chandos and Robert Knowles pleaded mercy. Du Guesclin cooled down, and there followed a feast with the ladies.
In 1363 Charles de Blois helped arrange Du Guesclins marriage. The bride, many years younger than her husband, as Tiphaine Raguenel, a noble lady whose father had been one of the combatants in the battle of the Thiry. She foretold destinies by the stars and was reputed as beautiful as she was learned, in double contrast to the bridegroom, who expended more labour writing his name than in delivering a sword thrust and was reputed as ignorant as he was ugly.
I the winter of 1365 Du Guesclin's strange army wound through southern France to the passes of the Pyranees, its appearance made the stranger by the adoption of the Crusader cross, in honour of a scarecely serious intention of fighting the Moors. The Pope at Avignon, who had had no success in trying to get rid of the brigands by excommunicating them, gave the expedition not only his blessing but a large sum in cash, though voicing to Du Guesclin the sarcastic complaint that normally sinners paid for their absolution rather than getting paid for it.
Du Guesclin is credited with a speech to his recruits that mixed the penitential with the profit-sharing motive:
"If we search out hearts, we have done enough to damn our souls ... We have ravished women, burned houses, slain children, exacted ransom from everyone, eaten their cows, oxen, sheep, stolen their geese, pigs, capons, drunk their wines, violated churches ... For God's sake, let us march on the pagans! ... I will make you all rich if you [follow me]!"