The history of the city of Gap is rooted in deep antiquity. Originally, this territory was inhabited by Celto-Ligurian tribes, specifically the Tricorii. In the Roman era, the settlement was named Vapincum. The first significant mentions of the city are linked to its function as a Roman military camp and a station on the strategic Via Cottia, which connected Italy with the Rhone Valley via Alpine passes.
The transformation of a small settlement into a significant regional center was largely due to its successful geographical position at a natural crossroads in the Southern Alps. Gap controlled access between Provence and Dauphiné, making it a vital transit point. The founding of a bishopric around the 5th century also played a decisive role in its development. The Bishops of Gap became the de facto rulers of the city, ensuring its administrative status and protection during the turbulent times of the early Middle Ages.
Thanks to its location on a trade route, Gap quickly established itself as a commercial hub. Already in the Middle Ages, the city was famous for its fairs and markets, which drew goods from the mountain valleys and the plains. The early economy was based on the wool trade, livestock farming, and leather craftsmanship, while cultural life centered for centuries around the cathedral and the bishop's palace, making Gap a center of spiritual influence in the region.