Saint-Maurice d'Agaune  is a Swiss monastery of canons regular in Saint-Maurice, Canton of Valais, which dates from the 6th century. It is situated against a cliff in a section of the road between Geneva and the Simplon Pass . The abbey itself is a territorial abbacy and not part of any diocese. It is best known for its connection to the story of the martyrdom of the Theban Legion, its original practice of perpetual psalmody, and a renowned collection of art and antiquity.The abbey is now the center of the picturesque village, which was vacated in the mid 20th century and is wholly owned by the territorial diocese. It is a Swiss heritage site of national significance.HistorySt. Maurice's Abbey is built on the ruins of a Roman shrine of the 1st century B.C. dedicated to the god Mercury in the Roman staging-post of Agaunum, and first came to prominence as a result of a now disputed account by Eucherius, the Bishop of Lyon. He had experienced a revelation that convinced him of the martyrdom of a Roman legion--known as the Theban Legion--under the command of Saint Maurice, around 285 A.D., in the area where the abbey is located.