In consequence of a chance circumstance he entered into relations with the dauphin Louis at that time (1455) in arms against the king his father; he attached himself to the prince, and followed him on his retreat into Burgundy.
[1] From the beginning of his reign Louis XI loaded Batarnay with favors: he married him to a rich heiress, Georgette de Montchenu, lady of Le Bouchage; besides making him captain of Mont Saint-Michel and giving him valuable estates, with, later, the titles of counsellor and chamberlain to the king.
As lieutenant-general in Roussillon in 1475 he protected the countryside against the wrath of the king, who wished to repress with cruel severity a rebellion of the inhabitants.
He was present at the interview between Louis XI and Edward IV of England at Picquigny, and was afterwards employed on negotiations with the duke of Burgundy.
He treated with Maximilian of Austria to prevent him from entering Picardy during the war with Naples, and then proceeded to Castile to claim promised support.