[8] Near Agaunum, in a place still identifiable as a former temple to Mercury, god of travellers, recently excavated behind the abbey's present sanctuary, a revelation led to the discovery of martyrs' bones during the time of Theodore, Bishop of Octudurum (now Martigny), who was in office 350.
The actual site of the martyrdom (or of the cache of bones) was pointed out to pilgrims as the "true place" the vrai lieu, a name it still carries, as Verroliez, according to local etymology.
In 515, the basilica became the center of a monastery built on land donated by Sigismund of Burgundy, the first king of the Burgundians to convert from Arianism to Trinitarian Christianity.
Between 515 and 521, Sigismund lavishly endowed his royal foundation, and he transferred monks from other Burgundian monasteries, to ensure that a constant liturgy was kept.
The liturgy, known as the laus perennis "perpetual praise" of relays of choirs, was an innovation for Western Europe, imported from Constantinople; it was distinctive to the abbey of St. Maurice and the practice spread widely from there.