The city of Briançon (then Brigantium) retreated to the northern part of its current location under the protection of the fortified peak overlooking the narrow valley of the Durance after the Migration Period (IV-IX centuries). The upper town was created according to a regular plan in the first quarter of the 13th century. Dominated by a castle since the 11th century, it did not require the protection of ramparts until the second half of the 14th century. Around 1344-1345, the town had four districts surrounded by a perimeter wall pierced by three gates and equipped with a royal house, a kiln, an alarm belfry, a market hall, a house of bankers, and three fountains. In 1370, the city wall was reinforced: the openings were blocked, the interstices between the houses were sealed, moats were dug, and towers were attached to the houses.