Duomo Nuovo: "Facciatone"
When a decision was made in 1339 to expand the existing Duomo, plans were drawn up for three new naves, a large semicircular apse, and radial chapels.
Less then a decade later, the Black Death visited the city, vastly reducing the workforce, and then when structural faults were discovered in the new construction, building work was brought to a halt in 1357. What can be seen today is the result of that short building period and is known as the 'New Cathedral'.
Already constructed was part of the new nave, the side walls, and the facade or 'Facciatone' which is attributed to Domenico d'Agostino. Part of the remains now houses the Museo dell'Opera del Duomo while the Palazzo Reale was built up against the left wall.
The side of the Facciatone facing the Piazza Jacopo della Quercia was originally intended to be the interior of the facade. It is finished in typical Sienese style with alternating bands of black and white marble while its three arcades give it a graceful lightness that attracts the eye.