San Fermo is a quite original church, since it consists of two overlapping churches.
It is dedicated to the saints Fermo and Rustico of the fifth century and right here the remains of the two martyrs were preserved and the church became a place of devotion. However, it was built by Benedictine friars in 1065. The Romanesque style of this first phase in white tuff, can be admired in the chapel, simply decorated with arches and votive frescoes. In 1260, the Franciscan friars built another church and the difference is quite noticeable. The second church was built in Gothic style alternating white tuff and red bricks. Its interiors, characterised by a Latin cross plan and a precious wood ceiling, hide a triumphal arch, are eccentric and finely decorated.
It also preserves invaluable works of art, such as frescoes from Pisanello, sculptures by the Michele Sanmicheli, the mausoleum designed by Niccolò Brenzoni and the chapel of the Alighieri family, heirs of the great poet.
Today, the bell tower hosts many bell ringing concerts.