The cathedral's history begins in the 9th century, when the first church rose on the ruins of an older temple. A second church was added to the south in the 10th century — this is the nave that survives today as the cathedral proper. By the 12th century, the two structures had merged into a single six-aisled Romanesque building. In the 13th century, one aisle was sacrificed to make room for the Paradise Cloister, an interlocking arcade of pointed arches in the Arab-Norman style that reflects the deep cultural exchange between Amalfi's merchants and the Islamic world. The bell tower, built between the 12th and 13th centuries, wears a crown of marble and majolica tilework that could belong to a mosque in Palermo or a palace in Marrakech. Each century left its fingerprint: Gothic chapels, a Renaissance altar, an 18th-century Baroque nave ceiling. The building is not one style but a conversation among many.

Beneath the cathedral floor lies the Crypt of Saint Andrew, accessible through a stairway leading down from the adjoining Basilica of the Crucifix. The relics of the Apostle Andrew — patron saint of fishermen and, fittingly, of a town that once commanded a maritime empire — were reportedly brought to Amalfi from Constantinople in 1206, during the upheaval of the Fourth Crusade. Whether the acquisition was pious rescue or opportunistic looting depends on which history you read, but the relics transformed the cathedral into a major pilgrimage destination. The crypt remains the emotional heart of the building, a low vaulted space where candles flicker against painted walls and the atmosphere shifts from architectural tourism to something quieter and older.

In 1861, part of the cathedral's original facade collapsed, damaging the atrium beneath it. The rebuilding fell to architect Errico Alvino, who designed a replacement that drew on Arab-Norman and Italian Gothic precedents — similar to the original but deliberately more ornate. The new facade, completed in 1891, features striped marble and stone, a deep porch with windows of delicate Arab-Moorish tracery, and a tall pediment crowned with mosaics depicting the Triumph of Christ, designed by the painter Domenico Morelli. The result is a front that looks ancient but is actually a Victorian-era interpretation of medieval aesthetics, built from admiration rather than preservation. Alvino's original designs are still held in the Amalfi Town Hall, a reminder that the facade visitors photograph today is an act of creative archaeology.

Inside, the cathedral's central nave is anchored by a high altar fashioned from the sarcophagus of Peter of Capua, who died in 1214. Above it hangs Andrea dell'Asta's painting The Martyrdom of Saint Andrew, part of a larger decorative program that includes dell'Asta's 1710 Miracle of the Manna on the boxed ceiling installed in 1702. The triumphal arch framing the sanctuary rests on two columns of Egyptian granite — material that traveled from quarries on the Nile to this small Italian coastal town, a journey that speaks to the reach of Amalfi's medieval trade networks. Two twisted columns and two pulpits survive from the original 12th-century ambo, and one pillar conceals a hidden interior column, a structural secret that reveals the Romanesque bones still supporting the Baroque surface. The cathedral rewards the slow visitor, the one who looks past the gilding to find the older building underneath.