The town increased in wealth and developed greatly during the Middle Ages thanks to the "Via Francigena" the trading and pilgrim's route that crossed it. Such prosperity lead to the flourishing of works of art to adorn the churches and monasteries. In 1199 it became a free municipality and fought against the Bishops of Volterra and the surrounding municipalities. Due to internal power struggles it eventually divided into two factions one headed by the Ardinghelli family (Guelphs) and the other by the Salvucci family (Ghibellines). On the 8th May 1300 Dante Alighieri came to San Gimignano as the Ambassador of the Guelph League in Tuscany. In 1348 San Gimignano's population was drastically reduced by the Black Death Plague throwing the city into a serious crisis which eventually led to its submission to Florence in 1353.

In the following centuries San Gimignano overcame its decline and isolation when its beauty and cultural importance together with its agricultural heritage were rediscovered.

The construction of the towers dates back to the 11th and 13th centuries. The architecture of the city was influenced by Pisa, Siena and Florence. There are 14th century paintings of the Sienese School to be seen and 15th century paintings of the Florentine School.

The Duomo or Collegiate Church, was consecrated in 1148 and is adorned with valuable Sienese School frescoes: "The Old and the New Testament" (Bartolo di Fredi and the "Bottega dei Memmi" or Barna da Siena); "The Last Judgement" (Taddeo di Bartolo) works of art by the Florentine school: "Stories of St. Fina" (Ghirlandaio), "St. Sebastiano" (Benozzo Gozzoli), wooden statues (Jacopo della Quercia) and the Sculptures (Giuliano and Benedetto da Maiano).

Frescoes, statues and sculptures make the Collegiate Church of San Gimignano a very prestigious museum.

The People's Palace: The People's Palace courtyard and Dante's Hall with "The Maestà" by Lippo Memmi. The Civic Museum and the Picture Gallery with works by Filippino Lippi, Pinturicchio, Benozzo Gozzoli, Domenico di Michelino, Pier Francesco Fiorentino, Sebastiano Mainardi, Lorenzo di Niccolò di Martino, Coppo di Marcovaldo etc... Entering from the Civic Museum the 54 metre high "Great Tower" or Podesta's tower built in 1311 can be visited.

The Museum of Sacred Art: Canvases, tablets, works in stone which come from former churches and monasteries, sacred silverware, vestements and psalm books.

The Archeological Museum, features Etruscan, Roman and Medieval findings from the city and the surrounding area. The Spezieria dello Spedale di Santa Fina ,reveals the techniques of the antique pharmacy, featuring ceramic and glass containers and medications.The Raffaele De Grada Gallery of Modern and Contemporary Art, is an important exhibition space for the city.

The Church of St. Agostino: Stories of St. Agostino (Benozzo Gozzoli), remains of frescoes dating from the 14th century, tablets and canvases by different artists (Benozzo Gozzoli, Piero del Pollaiolo, Pier Francesco Fiorentino, Vincenzo Tamagni and Sebastiano Mainardi). The Chapel of St. Bartolo (Benedetto da Maiano).