At the end of the 17th century, Briançon was surrounded by a medieval moatless wall from the end of the 14th century essentially made up of the back walls of the houses. This wall of poor condition and little defensive value was flanked by 4 towers and pierced by 3 doors. At the beginning of the League of Augsburg war, it was decided to reinforce the defenses of the city and to enclose it in a bastioned wall, almost without ditch or terraced rampart, erected as close as possible to the old medieval enclosure by demolishing several exterior houses and the parish church. This enclosure still constitutes the main part of the current fortification body.