Auchy les Hesdin is a commune in the Pas de Calais department and Nord Pas de Calais region of France. Auchy is situated on the D94 some 29 km (18 mi) east south east of Montreuil on the banks of the Ternoise, a tributary of the river Canche.
Formerly called Auchy les Moines, the village owes its origin to the monastery founded by Saint Sylvain, who came here from Toulouse in 700. Destroyed by the Normans, the monastery was rebuilt in the 11th century by the Counts of Hesdin, and entrusted to the Benedictine monks of St Bertin in 1072.
The pillars of the nave and the first span of the choir date back to the middle of the 12th century, the last two sections of the choir around 1200. They are the only remnants of the original church, which had to be almost entirely rebuilt after its collapse in 1280.In 1415, several of the knights killed at Agincourt were buried here, including the Admiral of France, Jacques de Chatillon.