The Barnabites, also known as the Clerics Regular of St Paul, named this church as Maggiore to distinguish it from two other San Paolo's in Bologna.
[2] Inside the building, the vaults were frescoed with scenes of the St Paul in the Areopagus of Athens by Antonio and Giuseppe Rolli.
The cupola, apse, sacristy and two chapels in the transept were frescored with quadratura by Pietro Farina, and figures by Giuseppe Antonio Caccioli[3] The main altar (1643-1650) features a dramatic marble sculptural group Beheading of St Paul (sculpted in Rome in 1634, but not in place till 1644) by Alessandro Algardi.
[4] The architectural setting of the altar, described by some as a Baldacchino, has Corinthian columns and a protruding portico is based on a design attributed to the architect Borromini.
In the third chapel has a Nativity and Adoration of the Magi by Giacomo Cavedoni, with a Flight to Egypt, Circumcision, and Jesus among the Doctors in the ceiling.