This church has been rebuilt in 1583 on the plant of an old church. An extension was built in 1680 by G.B. Bergonzoni. Santa Maria della Carità holds many important works of art by Galanino, Valesio, Cignani, Franceschini, Quaini, Crespi, Carracci, Gandolfi, Calvi and Bezzi.
The story of the crypt is linked to the birth of the first Christian community in Bologna. All the bishops of the Bolognese diocese were inhumed here until the 8th-9th century (except San Petronio buried in the complex of Santo Stefano).
The Church is famous above all because it preserves the remains of the priest and martyr San Valentino. Its name derives from the grada (a metal grille), still visible, through which the Reno Canal entered the walls of the city and that was mainly used to prevent possible enemies to enter the city.