The earliest sources make it the burial site of the martyrs Bassilla, Hermes and Protus and Hyacinth, all confirmed by inscriptions excavated from the catacomb and now in the Museo Pio Cristiano.
[2] Catalogues for medieval pilgrims add Crispus, Ercolanus, Leopardus, Victor and Maximilian or Maximus, but details of these extra saints' lives and deaths remain uncertain, confused and almost non-existent and no tomb monuments to them have been found in the catacomb.
It was built among very ancient earlier structures - some scholars such as Giuseppe Marchi identify these as the nymphaeum of a Roman villa, abandoned early in the 3rd century and converted to house human remains.
In 1940 the archaeologist Sandro Carletti discovered a niche with 11th - 12th century frescoes, including a bust of a long-haired bearded Christ with angels, an enthroned Madonna and child with the archangels Gabriel and Raphael and Saints Hermes, John the Evangelist and Benedict.
The marble slab closing the niche was inscribed Dp III septebr Yacinthus martyr - a copy is now on the site, with the original kept in the Pontifical Urban University on the Janiculum.