Riom was inhabited during the Roman era, from the 1st century through the 4th. During this time, it was a mansio or way-station along the Julier Pass road. After the Fall of the Western Roman Empire, farmers and herders continued to live here during the Early Middle Ages. In 840 it was personally owned by the king of Raetia Curiensis and was a local administrative center as well as the site of major church. The church was given by King Arnulf to a vassal of his named Ruotpert, who in 904 traded it to Lorsch Abbey. Riom and the surrounding lands eventually passed to the Knights of Wangen-Burgeis in the early 13th century and around 1226 they built Riom Castle.