The Church of San Domenico Maggiore is one of the largest and most important religious buildings in Naples. While the baroque interior of the church attracts the attention of most tourists, the sacristy hides many secrets.

Inside the sacristy, the balcony is adorned with 42 sepulchers of various members of the Aragonese royal family. They house various kings who ruled over the Kingdom of Naples between the 15th and 18th-centuries. Thirty-eight of these sepulchers still contain the embalmed remains of nobles, while the others have been moved to Spain. All the sepulchral arks were originally placed in the apse of the church, but were eventually moved to the sacristy. Each ark is covered by precious decorative cloths.

Other relics of Aragonese noblemen are stored in another area of the sacristy known as the Sacred Relics Chamber or Treasure Chamber. The collection is divided into four parts. The first part, the Aragonese Arches, contains clothing and accessories taken from the coffins in the sacristy. The second part is the Processions and contains the busts of a few saints that were carried in triumph by the Dominican order during religious celebrations.

The Treasure and the Sacred Ornaments are the last two sections and conserve liturgical vestments, along with other sacred objects from the long history of the basilica.