The Siena Cathedral, the Cathedral of Santa Maria Assunta, is one of the most captivating and mysterious places of worship in the whole of Tuscany. Its building work began in the second half of the 12th century and ended in 1313, when the bell tower was completed. A few years later, the idea of building a "New Cathedral" materialised and was an ambitious project that included the newly-built cathedral in this Cathedral, which was to be the largest in Europe. The plague and the dramatic economic conditions that affected the city around the middle of the 14th century led to the abandonment of the project, of which the facade remains as evidence. But it is inside Santa Maria Assunta that you can admire its most famous and enigmatic feature: the floor, the only monument in the world to be covered with multicoloured marble inlays that, in 1568, Vasari defined "The most beautiful, biggest and most magnificent floor that has ever been made." This decorative project lasted six centuries, from the fourteenth to the nineteenth century, and consists of more than sixty scenes created by over forty artists, including Pinturicchio, Domenico di Bartolo, Stefano di Giovanni di Consolo (aka Sassetta), Matteo di Giovanni and Domenico Beccafumi. A Renaissance floor, worked with the stone of heaven , and one of the most beautiful inlaid floors to be found in the world.
The facade is made of white marble with some Siena red marble and green stone of Prato decorations, divided into two halves - upper and lower - that refer to two distinct construction phases. The lower facade was built by Giovanni Pisano in Gothic Roman style: three portals with rounded arches and groups of Gothic sculptures, by Pisano himself, with prophets, patriarchs and pagan philosophers along with prophetesses. The upper part is attributed to Camaino di Crescentino and has a beautiful central oculus surrounded by Gothic niches, in which there are Apostles and Prophets paying homage to the Madonna with Child.
Inside the Church, one would expect to find depictions of the holy scriptures; but instead, in the Siena Cathedral, there are mythical characters who seem to have nothing to do with Christianity, such as the Sibyls and Hermes Trismegistus, in an incredible coexistence of pagan and Christian elements.
On the wall of the Cathedral facing the Archbishop's Palace we find the famous "Sator" or magic square, engraved with an airtight and palindrome inscription of five words, in turn composed of five syllables: SATOR, AREPO, TENET, OPERA and ROTAS. The Sator, or "magic square", is visible in numerous archaeological artefacts, scattered more or less everywhere in Italy and Europe.
Inside the Cathedral. there is a long row of 171 busts of popes, along with numerous capitals decorated with historical figures and located throughout the Church, many of which are believed to be the work of Nicola Pisano and his school. Below the popes, in the arches, there are 36 busts of emperors, probably a tribute to the city's Ghibelline tradition. The large rose window is closed by a stained-glass window depicting the Last Supper, painted by Pastorino dei Pastorini.