The historic centre is accessed directly from the town's main square, Roman Theater Square, which is overlooked by the Church of San Martino.

The square maintains the distinctive elliptical plan that traces the foundations of the ancient Roman structure. The ramparts of the theatre today serve as buttresses for the medieval houses that have been superimposed on the original structure.

The theatre was built following the Roman conquest of Corfinium. At the time of its construction in the first century B.C., it had a diameter of 75 meters and could seat about 4,000 spectators. Following a violent earthquake, the theatre was partially destroyed and dismantled piece by piece, until only the carving of its foundations in the ground was left. A plaque on the outside of the Valencian basilica commemorates this famous construction, located in the heart of the medieval settlement, opposite the mother church of St. Martin.

Now pause and walk to the entrance of the church.

The present structure dates from the restoration of 1489 to which other alterations were added following the 1706 earthquake. The late Romanesque portal of the facade dates from the 15th century: the stìpiti rests on a small stone base. Decorative plant and geometric motifs appear on the cyma of the two pillars, while a cross with palm leaves alternating with flowers is carved on the entablature. 

The interior is Baroque in style, with a single nave. The bell tower, a sturdy tower also used as a clock from the 1800s, completes the architectural picture.