Saint Sebastian was a soldier who was martyred during the reign of Diocletian (end of the 3rd century). He was pierced with arrows, then killed by blows of a club and thrown into the Cloaca Maxima in Rome. He appeared in a vision to the matron Irene, who subsequently picked up his body and carried it to the catacombs. His cult became very popular and in the 5th century a crypt was excavated around his tomb.
Catacombs of Saint Sebastian Rome
Address, opening hours and admission

Address: Via Appia Antica, 136 – Rome (tel. +39 06 7850350). Opening hours: 10,00 till 16.30. Closed: Sunday, January 1, December 25, 26. Admission: 8 Euros (age 6-15: 5 Euros; age 0-5: Free).
Mass
It is possible for groups celebrate mass in the Catacombs. This must be booked in advance. You need to bring your own priest, though.
History and description
The Appian Way, or the Via Appia Antica, passes through a valley near the Catacombs of Saint Sebastian. Since the bottom of the valley was called “ad catacombas“, the columbarii that were built there came to be called catacombs. Later the word became synonymous with all underground cemeteries.
Three mausoleums were erected at the bottom of the valley. In the 3rd century the church got ownership of the site and had the mausoleums covered by a platform, thus creating a so-called triclia (covered courtyard). In the 4th century a basilica was built on top of the earlier structures. This basilica was altered in the 13th century and renovated (by Cardinal Scipio Borghese) in the 17th century.
The Catacombs of San Sebastiano contain second century pagan as well as Christian tombs and consist of four levels. The tour will take you down a staircase along which remains of sarcophagi bearing imperial seals can be viewed. Underneath the church three pagan tombs can be seen, as well as some frescoes and a floor mosaic.
The first of these mausoleums is the Marcus Clodius Hermes Mausoleum, named after the owner whose name is written on the walls. Both the interior and exterior are painted and the vault is graced with the head of a Gorgo.
The second is the Innocentiores Mausoleum and has two rooms decorated with plaster and paintings.
The third is the Mausoleum of the Axe, named after the axe depicted on the pediment.
The Chapel of Symbols is called thus because of the early Christian symbols that can be found there.