City of Italy.
Christianity and the episcopate date back to the early part of the 2nd century.
Saints Vitalis and Agricola were martyred there during the Diocletian persecution.
In the 6th century it became a patrimony of the Holy See but in the 9th century was wrested from the popes.
Charlemagne made it a free city.
Weakened by internal struggles between Guelphs and Ghibellines, it lost its independence, regained it, and finally became a papal possession again, 1506.
In 1860, by an unanimous vote, it became part of the Kingdom of Italy.
The churches of Bologna are noted for their architectural beauty and art treasures, particularly the Cathedral of Saint Peter, 910, the church of Corpus Christi, erected by Saint Catherine of Bologna, and the shrine of the Madonna of Saint Luke, with its portico of 635 arches.
Bologna is also famed for its watch-towers, built by medieval nobles.
In the center of the city are two leaning towers, erected in the 12th century, the Asinella, 274 feet high, and the Garisenda, 137 feet high.
New Catholic Dictionary