Parts of San Gimignano's Romanesque cathedral were built in the second half of the 11th century, but its remarkably vivid frescoes, depicting episodes from the Old and New Testaments, date from the 14th century. Look out, too, for the Cappella di Santa Fina, near the main altar – a Renaissance chapel adorned with naive and touching frescoes by Domenico Ghirlandaio, depicting the life of one of the town's patron saints. These featured in Franco Zeffirelli's 1999 film Tea with Mussolini.

　　Entry is via the side stairs and through a loggia that was originally covered and functioned as the baptistry. Once in the main space, face the altar and look to your left (south). On the wall are scenes from Genesis and the Old Testament by Bartolo di Fredi, dating from around 1367. The top row runs from the creation of the world through to the forbidden-fruit scene. This leads to the next level and fresco, the expulsion of Adam and Eve from the Garden of Eden, which sustained some damage in WWII. Further scenes include Cain killing Abel, and the stories of Noah's ark and Joseph's coat. The last level continues with the tale of Moses leading the Jews out of Egypt, and the story of Job.

　　On the right (north) wall are scenes from the New Testament by the workshop of Simone Martini (probably led by Lippo Memmi, Martini's brother-in-law), which were completed in 1336. Again, the frescoes are spread over three levels, starting in the six lunettes at the top. Starting with the Annunciation, the panels work through episodes such as the Epiphany, the presentation of Christ in the temple and the massacre of the innocents on Herod's orders. The subsequent panels on the lower levels summarise the life and death of Christ, the Resurrection and so on. Again, some have sustained damage, but most are in good condition.

　　On the inside wall of the front facade, extending onto adjoining walls, is Taddeo di Bartolo's striking depiction of the Last Judgement – on the upper-left side is a fresco depicting Paradiso (Heaven) and on the upper-right Inferno (Hell). The fresco of San Sebastian under them is by Benozzo Gozzoli.

　　The church is commonly known as the 'Collegiata', a reference to the college of priests that originally managed it. An audio guide tour is included in the cost of entry. Joint tickets covering the Collegiata and Museo d'Arte Sacra cost adult/reduced €6/3, offering a saving of €1.50/1.