They fought hand to hand, and Ernauton de Sainte Colombe, an excellent man at arms, was on the point of being killed by a squire of the country called Guillonet de Salenges, who had pushed him so hard that he was quite out of breath, when I will tell you what happened: Ernauton de Sainte Colombe had a servant (un varlet) who was a spectator of the battle, neither attacking nor attacked by any one; but, seeing his master thus distressed, he ran to him, and, wresting the battle-axe from his hands, said, 'Ernauton, go and sit down: recover yourself: you cannot longer continue the battle.' With this battle-axe he advanced upon the squire, and gave him such a blow on the helmet as made him stagger and almost fall down. Guillonet, smarting from the blow, was very wroth, and made for the servant to strike him with his axe on the head; but the varlet avoided it, and grappling with the squire, who was much fatigued, turned him round, and flung him to the ground under him, when he said, 'I will put you to death, if you do not surrender yourself to my master.' 'And who is thy master?' 'Ernauton de Sainte Colombe, with whom you have been so long engaged.' The squire, finding he had not the advantage, being under the servant, who had his dagger ready to strike, surrendered on condition to deliver himself prisoner within fifteen days, at the castle of Lourde, whether rescued or not. Of such service was this servant to his master; and, I must say, sir John, that there was a superabundance of feats of arms that day performed, and many companions were sworn to surrender themselves at Tarbes and at Lourde.
Froissart, Jean, and Thomas Johnes. The Chronicles of England, France and Spain: And the Adjoining Countries, from the Latter Part of the Reign of Edward II, to the Coronation of Henry IV. London: William Smith, 1844. Print. Vol. 2. pp 98-99
We should not assume that Ernauton's servant was completely unarmored: valets could be equipped with significant arms and armor, although we cannot assume that Ernauton's servant was, and his role as spectator to the battle before the direct threat to his master's life suggests that he wasn't.