The crypt, from the Latin crypta meaning hidden, is an underground space, usually located under the floor of the presbytery, where the relics of saints or the tombs of eminent figures were kept. The crypt was more common in churches of the early medieval period when it was also used as a small chapel.
The crypt of Palermo Cathedral is an environment outside the church, leaning against the three apses, rectangular in shape, partly above ground. It was once a place of worship known as the “Cemetery of All Saints”, with direct access from the “Cathedral Floor”.. Today, it can be accessed through some internal passages located in the two side apses.
The hall is divided into two naves with cross vaults, which rise on the perimeter walls and are supported by fourteen columns, almost all in Egyptian granite, surmounted by spolia capitals. The crypt houses 23 tombs from the Roman era with the remains of the archbishops of the Cathedral, including Gualtiero.
The crypt has been believed by many scholars to be a structure from the period before the Norman cathedral. Recent studies, supported by archaeological research, have shown that the crypt was built later than the construction of the apses, i.e. in the 12th century, after the transformation of the church by Archbishop Gualtiero.