Some traces of a Bronze Age settlement were found at the foot of the rocky spur in town. There was a Roman era town at Saint-Maurice, but very little is known about the actual layout of it. There was a customs post at Acaunum, where an import and export tariff of 2.5% was levied. The town probably had a shrine to water nymphs. According to tradition, Saint Maurice and his southern Egyptian companions of the Theban Legion were martyred in Acaunum during the reign of Maximian (286-310). Around 360-370 Theodul, the first Bishop of Valais, built a basilica in Acaunum in their honor. The basilica became a popular pilgrimage site. In 515, the King of Burgundy Sigismund founded the Abbey, which he endowed with rich land.