Article révisé par les pairs
Résumé : Located at about 50 km from the North Sea (Boulogne), the town of Thérouanne, which was the chief town of the Gallic city of the Morins, extended at the end of the 3rd century AD, on almost 140 ha. The existence of an episcopal group from the 7th century and a cathedral from the Carolingian period reveal the status and importance it had in the Middle Ages. Enclosed by a powerful rampart and dominated by a castle, it controlled part of the access to the coast and suffered numerous assaults, notably during the Hundred Years War. At the beginning of the 16th century, which became a royal French enclave in the imperial territory of the Netherlands, it was besieged unsuccessfully in 1513 by Henry VIII of England, then in 1537 and in 1553 by Charles V, to whom the city finally surrendered after two months of siege. The city was then completely razed and all reconstruction was forbidden. Since then, the site known as the "Old Town", returned to agriculture, constitutes, due to the vicissitudes which it has crossed, an exceptional deposit for the knowledge of the ancient and medieval history. The paper will present the multidisciplinary research program undertaken since 2015 in order to reconstruct the urban and peripheral landscape, to understand its evolution under the pressure of the ecclesiastical and lay authorities, to identify the economic dimension of this stronghold and to draw up its network of exchanges.