with the exception of the two chapels in the Renaissance style. The facade, which has little ornament, is approached from the square by a wide staircase and has a door into each of the side aisles, but no central portal. The doorways are surmounted by stone lintels with recessed arches above them, unusual in incorporating the stone Gabbro. There is a central ocular window at the end of the nave and a smaller one giving light to each aisle. The facade, which is stone, was raised higher in brick in 1340, when the ribbed vaulting was constructed, and the two smaller ocular windows set in. Matteo di Brunisend is generally credited as the main architect of the medieval period, with his date of activity given as 1239, but in fact his contribution may have been little more than the design of the central ocular window. Beneath this window is a slot which marks the place of a window which lit the chancel of the earlier church, and may be the most visible sign of the church's reorientation in the 12th century rebuilding, although this is not entirely agreed upon by scholars. To the north side of the church, in the corner of the transept and chancel, stands a severely plain campanile of square plan, with a single arched opening in each face. The campanile may be that of the earlier church, as it appears to mark the extent of the original western facade, or it may have been one of the city's many tower houses, pressed into service of the church. To the south side of the church is the Loggia of the Baptistry, a 14th-century arcaded cloister with stout octagonal columns and a groin vault. Internally, the building is in the shape of a Latin Cross, with central nave and an aisle on either side, divided by arcades of seven semi-circular Romanesque arches resting on columns with simplified Corinthianesque capitals. The chancel is a simple rectangle with a single arched window at the terminal end. The roofs throughout are of quadripartite vaults which date from the mid 14th century. Although Gothic by date and decoration, the profiles of the ribs are semi-circular in the Romanesque manner. The clerestory has small windows, inserted when the nave was vaulted, along with lancet windows in the north aisle, the aisle windows were subsequently blocked for the painting of the fresco cycle, making