 An old tradition claims that 10,000 Christian slaves who died while building the Baths of Diocletian are buried in the church's crypt, and are venerated as St Zeno and Companions.Some dead slaves from this project are likely buried in catacombs in the nearby hillside, though the 10,000 figure must be exaggerated.According to legend, St Bernard had a vision while celebrating a requiem mass at the church.