 The Duke of Alba, commanding a force of 3,000 infantry and 300 cavalry supported by a further 400 artillerymen, occupied the Pyrenean valleys of Aezkoa, Salazar, and Roncal.They crossed the Pyrenean passes northbound, taking the Chapel of Roncevaux by surprise, and setting fire to the village.The Castilian forces spearheaded by Colonel Villalba (or the Beaumont party lord Martin of Ursua, depending on sources) arrived in Saint-Jean-Pied-de-Port on 10September, only to find that its garrison under the lord of Miossens (an Albret) was abandoning the stronghold.