Gavino, Proto and Gianuario, persecuted by the emperor Diocletian, were martyred in the Roman colony of Turris Libisonis - now an archaeological area - in the early 4th century. A majestic monument built in the 11th century and wrapped in the mystery of legendary stories, was dedicated to them. The Basilica di San Gavino stands on the Monte Agellu in the centre of Porto Torres, on what was originally a Roman and paleo-Christian necropolis, and later the site of two churches (5th-7th century), the remains of which were incorporated into the crypt. You can walk down the gallery dug to hold the martyrs relics, in artistic tombs, discovered in 1614 and now objects of pilgrimage for thousands of pilgrims. Admire the array of archaeological finds from the excavations, kept in the AntiquiariumTurritano, including tombs decorated with mosaics and frescoes, statues and a Byzantine cistern.