Volterra still retains its medieval character, charm and atmosphere. Its isolated position has impeded any progressive development. The defensive wall built in the 13th century was the result of an urban development that began in the year thousand and was completed at the beginning of the 14th century.
In the 5th century the city was reduced to a castrum which developed around the early church of Santa Maria(the cathedral) and the Pratus Episcopatus(Piazza dei Priori) and included the Piano di Castello, Porta all’Arco, via Roma, via Buonparenti, via dei Sarti and via di Sotto.
Borgo di Santa Maria, the present via Ricciarelli and the Borgo dell’Abate (via Sarti) were beyon the castrum or castellum.
The boundaries of the Prato were delimited by powerful groups of towers; the crux viarum of Buonparenti, Sant’Agnolo and Baldinotti..
During the 13th century, the domus comunis (Palazzo dei Priori) was erected , the main square was defined and the height of the towers restrained.
Behind the Palazzo dei Priori arose the religious square, the Piazza S.Giovanni which included the cathedral, the baptistry, la casa dell’Opera, the hospital of Santa Maria and the cemetery (the present via Turazza).
The medieval structure has remained almost unchanged throughout the centuries and is still circumscribed by the four main medieval peripheral districts of Borgo di S.Alessandro, looking over the Cecina valley; S, Lazzaro towards Florence and Siena; S.Stefano and S.Giusto. The latter, the farthest from the city, is near the Balze, dominated by the majestic church dedicated to the patron of the city , San Giusto.
At the end of the 19th century the psychiatric hospital was built in the S.Lazzero area. Once an extensive complex it has recently been transformed into a hospital.
In the same area of S.Lazzero there is also the old railway station opened in 1912 that connected
the city to Saline.