Few places hold so much of Bologna's history in so little space. The Italian national tourism portal counts seven parts: four churches, the Crocifisso, the Santo Sepolcro, Santi Vitale e Agricola and the Trinità, two open-air spaces, the Benedictine cloister and Pilate's Courtyard, and a museum. Walking from one to the next you pass Roman, Byzantine and Lombard remains, and the Comune calls the complex Bologna's most important example of sacred Romanesque architecture.
The layers go deep. The regional heritage catalogue records a Roman temple of Isis on the site, the relics of the martyrs Vitale and Agricola placed here by Saint Ambrose in 392, and a replica of the Holy Sepulchre built by Petronius, bishop from 431 to 450, who was buried in it. The Lombards made it their main religious centre in 727, and much of the Romanesque look you see today comes from restorations between the late 19th century and 1931.