The Cathedral of Santa Maria Assunta was conceived and carried out in the XII century, around the year 1120, but its current outward appearance was the result of further works carried out in the following centuries after the passage of Volterra under the control of Florence.
The façade is the part of the dome that better represents the periods when numerous artists worked here. It was originally planned together with the building in the XII century and its portal, created using Roman materials, was inserted in the following century.
The decoration works, made by Nicola Pisano, were added later. The aisles on the interior of the building show the Renaissance influence, even though it has a Romanesque, Latin cross shaped layout.
In the first decades of the XVI century, the six Montecatini stone altars were built. At the end of the XVI century, the church underwent further alterations.
After the Council of Trent, which the Bishop of Volterra strongly supported, adaptation works were made in all the worshipping places.
Inside the cathedral, columns and Roman capitals were chiselled and plastered over and the ceiling, where Jacopo Pavolini carved the sketches of crosses, geometrical figures and images of saints previously prepared by Francesco Cipriani, was redrawn.
Around the central nave where the Holy Spirit (the Paradise) is depicted, many busts representing the saints (St. Ugo and St. Giusto, the Pope St. Linus, St. Clemens, Ss. Attinia and Greciana) are distributed. At the centre of the transept, the Assumption of the Virgin Mary in the Sky is depicted and, near, there are St. Vittore and St. Ottaviano. Both the Medici and the Serguidi families and, eventually, the town itself wanted to put their emblems on the triumphal arch.
Other restoration works were carried out in the XIX and the XX centuries. The first renovations were performed between 1842 and 1843 and they concerned the painting of the church with trompe l'oeil panels, the repairing of the floor, the new decoration of the columns in pink granite and the restructuring of the presbytery. The works of 1934-1936, instead, were due to a fire that damaged the cathedral. These works allowed the recovery of the ancient gothic workmanship of the transept.