ADRIA, DIOCESE OF. — Adria, now 22 km from the open sea, had a very active port during the Roman Republic; until the 10th century it remained the only important centre between the Po and the Adige. Today it is a small town in the province of Rovigo, on the Po di Levante, and is an episcopal see.
Doubtful traditions would trace the introduction of Christianity to Adria to the apostolic age; it must instead be placed at the end of the 2nd century. The see of Adria existed from an uncertain period, but is first mentioned as such in the 7th century, when the name of its bishop GALLONISTO appears in the Roman Synod of 649. Around 920, Paul, bishop of Adria, authorized by a bull of John X (Jaffé-Wattenbach, no. 3561; PL 132, 804), transferred his see to Rovigo, which from that time became the seat of the bishops of Adria and where, in 938, his successor John began the construction of the cathedral. In Adria the present cathedral, dedicated to SS. Peter and Paul, was built in the years 1776–1836. The bell tower dates from 1686; and inside there is a 6th-century bas-relief with a Greek inscription depicting the Madonna and Child with angels.
Dependent on the archdiocese of Ravenna since the beginning of the 19th century, Adria passed in 1818 to the patriarchate of Venice. The diocese has 97 parishes with 269,500 faithful, 198 diocesan priests and 30 regular clergy.