There was already a cathedral on the site (on the present Via Indipendenza) in 1028, accompanied by a pre-
Romanesque campanile with a circular base (in the architectural tradition of
Ravenna). This church was destroyed by a devastating fire in 1141. It was reconstructed and consecrated by
Pope Lucius III in 1184. In 1396 a high
portico (
protiro) was added to the west front, which was rebuilt in 1467. From about 1477 the
Ferrarese painters
Francesco del Cossa and
Ercole de' Roberti worked in the Garganelli Chapel on the creation of a cycle of
frescoes which later had a significant influence on
Niccolò dell'Arca and
Michelangelo. The frescoes were lost in subsequent reconstruction except for a very few fragments. In 1582
Pope Gregory XIII elevated the Bishop of Bologna to Archbishop, and accordingly the cathedral was elevated to the rank of "metropolitan church" (a bishop's seat with jurisdiction over other bishops and dioceses in its territory). By order of Cardinal
Gabriele Paleotti a radical remodelling of the interior of the building began in 1575, of which the
crypt and the Greater Chapel (
Capella Maggiore) survive. The alterations were so extensive however as to cause the vaults to collapse in 1599, and the decision was then made to rebuild the main part of the cathedral from scratch. Work on the new building started in 1605. A new façade was added between 1743 and 1747, to designs by the architect
Alfonso Torreggiani, on the instructions of
Pope Benedict XIV. == Description ==