The Ramparts, a major element in the urban scenery, are witnesses to 1500 years of military history.
At the end of the 3rd century, while the Roman Empire wavers, Vannes, then callled Darioritum, is authorised to fortify itself. A castrum (or fortified site) is built to the west of the Gallo-Roman town, on the Méné Hill. The triangular defensive wall protects a surface of around 12.5 acres.
During the early Middle-Ages, the castrum becomes the heart of the medieval town. Restorated during the 13th century, the fortifications are made bigger between 1370 and 1390 by the duke of Brittany Jean IVth ; the inner town doubles in size. On the south-western flank of the new wall, is the château de l’Hermine (now gone), near the porte de Calmont. Battlements, gunports and towers complete the defensive system during the 15th century.
At the end of the 16th century, the medieval walls are reinforced with bastions to answer the needs of modern artillery. The “éperon de la Garenne”, built between 1626 and 1628 by the architect Augereau, is the last defensive structure built in Vannes.