The Cathedral, dedicated to San Martino, is in the homonimous square. According to the tradition, it was founded by San Frediano during VI century, then rebuilt in 1060 and at last restored and changed between the XII and XIII century.
San Martino received the title of cathedral church in VIII century. Sign of this important role was the translation, in the year 780, of the relics of San Regolo in the new cathedral. Then it was necessary the widening of the church, with the construction of a crypt, and new and more elegant furnitures.
The cathedral was completely rebuilt from 1060 and solemn consecrated in 1070. In XIV the century it was restored: in 1372 the apse, the walls of the transept and the first span were completed. The nave was still the Romanesque one. In the porch, open on the square through three large arches, there are some bas-relief representing the martyrdom of san Regolo, a cycle of the months and the history of San Martino. Inside we can see the Tempietto of Matteo Civitali where there is the Volto Santo of Lucca, that is the wooden crucifix carved between XI and XII century, perhaps as imitation of another one, more ancient, of byzantine origin. It is celebrated on the 14th of september, day of Santa Croce.