Today the Piazza Duomo is still the heart of San Gimignano, just as it was the centre of political and religious life in the Middle Ages. It marks the intersection between the Via Francigena (running north to south) and the old Pisa-Siena Road (running east to west).
It is a brick, trapezoid-shaped space with a slight slope, adding to the wonder of those who upon entering find themselves all of a sudden at the centre of the Middle Ages. Three important medieval buildings face one another here: On the north side, projecting up into the sky, are the Torri Gemelle dei Salvucci. On the opposite side is the Palazzo Nuovo del Potestà with the Loggia del Comune. Beside it is the massive Torre Grossa.
The most imposing building is the Collegiata; it is at the centre, overpowering the piazza with its bulk as it sits on high atop a stairway. Exactly opposite is the Palazzo Vecchio del Potestà with the Torre Rognosa and the Torre Chigi alongside.
The Collegiata, also know as the Duomo, gives its name to the piazza and has been there since the 11th century. In the first half of the 13th century, during the period of greatest economic prosperity, the piazza assumed the appearance it still has today. The main public buildings were built here, and the façade of the Duomo was rotated to face the Palazzo Vecchio del Potestà.
The Chiesa Collegiata, the Duomo of San Gimignano, dates from the 12th century. It is a splendid building with all of its medieval features preserved. It is considered one of the best examples of the Tuscan Romantic Style.
There is a breathtaking view of the addition in the interior. Splendid frescoes also completely cover the walls of the three naves, a concentration of priceless works of art.
The decorations depict stories from the Bible and the lives of saints. Artists with work here include: Benozzo Gozzoli, Domenico Ghirlandaio, Taddeo di Bartolo, and Jacopo della Quercia, who created the wooden Annunciation.
The oldest paintings are those on the internal façade directly above the entrance. They date back to the 1300s, but some of them are indecipherable. Only certain figures are recognizable, such as San Nicola and a Madonna with Child. There is also an ancient apse on this wall, since the church was in fact originally oriented in the opposite direction from how we see it now.
The right nave is decorated with large frescoes depicting stories from the New Testament. The central scene, the Crucifixion, occupies two levels. This fresco cycle represents one of the most important examples of European Gothic Art.
Toward the end of the nave is the Chapel of Saint Fina, a native of San Gimignano who became the protector of the city. Her remains are preserved under the altar. The Chapel is an example of early Renaissance style, although it underwent various restorations between 1700 and 1800.
The side walls were decorated by Domenico Ghirlandaio, who also worked on the Sistine Chapel. The fresco that depicts the funeral of Saint Fina could be considered a snapshot of San Gimignano in 1400. The scene shows the church, where the body of the saint lies at rest, opening out to offer a glimpse of the city with towers projecting up in the background. Some of the figures represent the miracles during the life of Saint Fina. Up high on the left, an angel touches the bells in one of the towers, making them ring.
On the chancel there is a ciborium from the 1400s.
The left nave is frescoed with stories from the Old Testament. One of the more suggestive scenes is the Creation of the World, with Earth shown at the centre of a blue disc sky.