The Pic du Midi d'Ossau was reputedly first climbed in 1552 by an expedition led by François de Foix-Candale, later to become the Bishop of Aire. Although the success of this first climb is disputed, it is known that the mountain had been successfully climbed by 1787 when a military surveyor noted that a triangulation cairn had been built on the summit. The first fully recorded climb was by Guillaume Delfau accompanied by Mathieu (an Eaux-Bonnes shepherd) on October 2, 1797.