Around the year 500, under the Bishop Basilius, a group of episcopal buildings was constructed on top of the old Roman forum, including a chapel, a baptistery and several other rooms [REF].
At the beginning of the 12th century, a new church was begun on the same site, with Romanesque walls bearing the three bays of a wide single nave, constituting a parish church dedicated to the Virgin Mary (Notre Dame de la Sède).