ADRIA, DIOCESE of. — A., now 22 km from the open sea, had a very active port during the period of the Roman Republic; and until the 10th century it remained the only important center between the Po and the Adige. Today it is a small town in the province of Rovigo, on the Po di Levante, and is the seat of a bishopric.
Dubious traditions would date the introduction of Christianity into A. to the apostolic age; it should instead be assigned to the end of the 2nd century. The seat of a bishopric from an uncertain date, it is first mentioned as such in the 7th century, when the name of its bishop Galvanisto appears in the
Roman Synod of 649. Around 920 Paolo, bishop of A., having received authorization by a bull of Giovanni X (Jaffé-Wattenbach, no. 3561; PL 132, 804), transferred his see to Rovigo, which from that moment became the see of the bishops of A. and where, in 938, his successor Giovanni began the construction of the cathedral. At A., the present cathedral, dedicated to ss. Pietro and Paolo, was built in the years 1776–1836. The bell tower dates from 1686; and inside, a 6th-century bas-relief, with a Greek inscription, depicts the Madonna with Child and angels.
Dependent on the archdiocese of Ravenna since the beginning of the 19th century, A. became part of the patriarchate of Venice in 1818. The diocese has 97 parishes with 269,500 faithful, 198 diocesan priests, and 30 religious priests.