ODERZO (Opitergium). – Ancient diocese of the Patriarchate of Aquileia, now in the diocese of Ceneda, presently known as Vittorio Veneto. A city of the Veneta Euacariana, in the province of Treviso, situated 16 meters above sea level on the right bank of the Monticano River. The comune has a population of 17,000 inhabitants, the capital 7,000: agriculture is flourishing and the production of wheat and silkworm cocoons is abundant; a railway line connects it with Treviso-Portogruaro.
Of pre-Roman origin, Oderzo was established on a slight quadrilateral plateau, soon becoming an important center along the route of the Via Postumia; in 88 BC it was a Roman colony and then a municipium belonging to the Papiria tribe; around 44 BC it was rebuilt by Caesar after the destruction by the Pompeians (49 BC). A vital road junction, during the imperial era it was destroyed by the Quadi and Marcomanni in 169 AD, suffered severe damage from barbarian invasions, so much so that substantial nuclei of inhabitants, particularly during the sack by Attila and the Lombard occupation, transferred their residence to the lagoons, giving rise to Heraclea.
Christianity penetrated relatively late, as in other centers of the “Venetia et Histria”; with good probability (a paleochristian epigraph of Sabiniana, Bishop Epodius from the early 5th century), it was well organized in the second half of the 4th century, when the episcopal see was established, which, after Marcianus, continued until the 7th century.
In 667 Grimoald destroyed Oderzo and divided its territory among Friuli, Treviso, and Ceneda. From this moment Ceneda, which was the center of a duchy, probably became the episcopal see, while Oderzo, after a period of abandonment, slowly revived to flourish in the best times of the Venetian Republic.
Art. – The civic museum, arranged in rooms of the Town Hall, houses monuments and furnishings from the Roman period, a respectable coin collection from the imperial era, capitals, columns, examples of funerary sculpture with fine portraits; the black-and-white mosaic floors, and particularly others with hunting scenes (late 2nd century AD), are splendid in their depiction of life and movement, harmonious in color within a vivid range of impressionistic taste. Other museums with remains of Roman houses have recently reappeared (1951) through the work of the “Associazione amici di Opitergium,” an association that aims to reconstruct the history and topography of the ancient city through systematic excavations. From the Renaissance are some arcaded houses with frescoes, which give Oderzo a characteristic appearance, creating a picturesque and monumental zone in the main square. The 15th-century cathedral, recently restored, with a single nave of ample spatial design and a raised tripartite apse with an elegant dome, stands on earlier paleochristian and medieval constructions, has frescoed walls (15th century) and preserves a Roman mosaic carpet with yellow frames, reused in the presbytery, paintings by Palma the Younger, by Pomponio Amalteo (organ shutters), by Bellunello (Madonna), bas-reliefs with the Virgin on a throne and in a tabernacle (Venetian art of the 14th century from the school of De Sanctis and with Pisan influences).