The Cathedral Church, dedicated to Santa Maria della Purificazione (Saint Mary of the Purification), is located in the heart of the Borgo Vecchio, on the site of the oldest urban settlement, as evidenced by some archaeological finds dating back to the Bronze Age, surrounded by low houses in a square plaza from which, in many places, one can enjoy the splendid view of the port, the sea, and the mountains of nearby Abruzzo (Maiella). The first structure was built, presumably, on the ruins of an ancient pagan building of which, however, there are no traces, but which was probably erected in 1037 above the remains of what was once a pagan temple dedicated to Castor and Pollux, two Dioscuri, that is, figures from Greek and Roman mythology, twin sons of Zeus. There are, instead, clear traces, such as the circuit of the three apses and the floor mosaic, of a religious building that predates the current one and was already a Cathedral, dedicated to St. Mary of the Purification. During the 12th century, two earthquakes seriously damaged the "mosaicked" Church, and it was therefore decided to build a new temple. The Cathedral is divided into three naves by cruciform pillars and has a truss roof in the central nave and cross vaults in the side aisles. Over the centuries, the Cathedral suffered natural disasters and looting that severely devastated it. In the mid-18th century, the interior underwent a Baroque transformation from which it was freed in the 1930s, when the floor mosaics and the remains of the apses of the pre-existing religious building came to light. With recent restoration work, other parts of the floor mosaic and a large cemetery area beneath the sacristy rooms have been uncovered, dating back to the 9th century in the oldest layers. On December 31, 1761, the bones of St. Bassus, patron saint of Termoli, were found in the crypt of the Cathedral; while, in May 1945, those of St. Timothy, a disciple of St. Paul, as well as those of some bishops, were found there. Currently the cathedral is 22 meters high, the facade stands two meters above the ground, it is formed by an older part enriched with carvings, and on the upper part there is the rose window. In the lower part there are seven arches, each different from the others and decorated with leaves and human figures, while the central arch, larger than the others, has a portal with bundles of small columns. The interior has been restored to its original state following renovation work that began in 1932. The layout of the Cathedral is basilican, with three naves and three semicircular apses with circular-based pillars.