Supported by a massive rounded arch, the walls of this room are richly covered with thirteenth century frescoes, discovered in 1937: Last Supper and Washing of the Feet (left wall), Annunciation (on the large arch), Passion, Christ in Glory and Christ the Judge (beyond the large arch), St. Narnus and St. Viator, the city's first Bishops, (in a double lancet window), and St. Alexander on horseback (in a mullion and in the lunette).
