The ancient Aquileia, rich cities of the Roman Empire, is the complete example of a Roman-Mediterranean city. The Patriarchal Basilica was decisive, then, for the development of Christianity. Founded by the Romans (181 BC) in the plain of the Po, it was a great trading center between Europe and the Mediterranean: rich citiy, in 90 BC became the center of public buildings, private homes, imperial residences and the Mint. Destroyed in 452 by the Huns of Attila; is Venice that gived back to it a merchant role keeping to the seat of the patriarchate until 1751. The excavations have revealed the Forum, the Roman Basilica, the Macellum, the bathrooms and two luxury houses as well as a cemetery, the amphitheater, the circus and the port facilities, the warehouses and the docks along the river. The Basilica of Aquileia was born in the form of “U”, it was expanded in 345, then destroyed by the Huns and rebuilt thanks to Bishop Maxentius and to Charlemagne. In romanesque style, has a large mosaic (4th cent.) with scenes from the Gospel, the Apostles and fishermen story of the prophet Jonah. The crypt of the frescoes, (6th c.) houses the relics of martyrs. In the Crypt of the Excavations are preserved rich mosaics with esoteric references (I sec.), And from the west entrance, leads to the octagonal Baptistery and the baptismal pool with the monogram of Christ, surrounded by a colonnade. Finally the imposing bell tower, erected in 1031. The monastery complex (4th cent.), now a museum, houses a remarkable floor mosaic.