MONS BRISIACUST his is one of the positions in the Roman Itins. along the Rhine. They place it between Helvetum or Helcebus [HKLCEBUS] and Urunci. There is no doubt that is Vieux-Brisachor Altbreisach, as the Germans call it. All the positions of the Itins. on the Rhine are on the west or Gallic side of the river, but Vieux-Brisachis on the east side. The Rhine has changed its bed in several parts, and this is one of the places where there has been a change. Breisachis described by Luitprand of Pavia (quoted by D'Anville), as being in the tenth century surrounded by the Rhine in modum insulae.It may have been on an island in the Roman period. The hill (mons) of Altbreisachis a well marked position, and was once crowned by a citadel. Altbreisachis now in the duchy of Baden, and opposite to Neubreisachon the French side of the Rhine.
[G.L]