Bertrand du Guesclin: Careerist in Arms?

Like the reputation of Napoleon, that of the constable of France, le bon Breton, Bertrand du Guesclin, subsists despite his evident defeats at the hands of the enemy and several episodes in his long career as a soldier which cast their shadow over his motives and his actions. Eulogised for his patriotism by nineteenth- and early twentieth-century historians, he had already become a legend within his own lifetime (c. 1320-80), and in the decades immediately following his death his fame was widespread. Who was the person behind this enigma? What were his springs of action? Can he in any sense be described as a patriot, and if so a patriot for whom?