CATACUMBS, Cemetery in. — From the Greek κατά and κῶμαι, it was originally a topographical designation used for the depression along the Via Appia between the second and third milestones, specifically between the present church of St Sebastian and the tomb of Cecilia Metella. The term is clearly attested in the Chronography of 354 in the Depositio martyrum on 20 January and 29 June, which commemorates St Sebastian and St Peter respectively, and in the Chronica Urbis Romae for the circus dedicated by Maxentius in AD 309 in honour of his son Romulus.
In this area lies one of the most important and complex monumental complexes of Christian subterranean Rome; it has been the subject of numerous studies, especially since 1915 when the Memoria Apostolorum was brought to light. The monuments comprising it date from the 1st to the 4th century AD. At the original level of the depression, the remains of a private road crossing the Via Appia are still visible: on its north side stood a two-storey private house and other buildings very likely connected with funerary worship. Two series of columbaria were built on the same side of the road: in one of those closest to it, an inscription still in situ of a freedman of Vespasian clearly dates it to the 1st century, while those of the other series are somewhat later. In the latter, however, there are also Christian elements (paintures and inscriptions) from the first half of the 3rd century: a sign that the owners had embraced the new faith.
Towards the middle of the 3rd century, a partial infilling of the depression took place and a kind of trapezoidal courtyard with a sloping floor was constructed: the so-called Triglia. It was certainly a place of Christian gatherings since the walls of this courtyard are covered with graffiti which, besides referring to the rite of refrigerium, to vows or their fulfilment, almost unanimously in Greek or Latin mention prayers addressed to the Apostles Peter and Paul. The discovery of these graffiti was made in 1915 and the monument was commonly called Memoria Apostolorum. As to the nature and purpose of the Memoria, however, scholars are divided. Ancient literary traditions (Liber Pontificalis, Martyrologium Hieronymianum, Itineraria, Passiones) all refer to a temporary burial of the Apostles Peter and Paul in the Catacombs; none, however, specifies the site more precisely, nor have excavations revealed anything positive and definitive. The study of literary sources has divided authors into three groups: 1) the Memoria is a true sepulchral monument arising from the temporary burial of the bodies of the Apostles Peter and Paul, either immediately after their martyrdom and before their final placement in the Vatican and on the Via Ostiensis, or in AD 258 during the persecution of Valerian; 2) the Memoria was built to commemorate the dwelling of the two Apostles while alive in one of the houses in the Catacombs; 3) the Memoria arose in connection with the institution of a liturgical feast in honour of the two Apostles in the Catacombs, begun in AD 258, when, because of Valerian’s persecution, Christians were forbidden to enter cemeteries and thus could not venerate the tombs of the Apostles in their respective places.
In the first half of the 4th century a new and more extensive infilling was carried out: all the pre-existing monuments, both pagan and Christian, were sacrificed for the construction of the grand basilica Apostolorum, as it was originally called. In its original structure, this basilica presented a unique architectural form in the Christian basilican tradition: the side aisles were not separated by columns but by brick piers which formed almost a kind of ambulatory at the back of the apse. It seems that the basilica was intended as a burial place; numerous mausolea were indeed opened along the perimeter walls. The most important of these is the one on the left side of the apse, commonly called the Platonia, in which Pope Damasus placed one of his poems, and in the 5th century the body of the martyr Quirinus of Siscia was transferred there following the invasion of Pannonia by the barbarians.
Before the construction of the basilica, however, an underground cemetery had begun in the Catacombs in which were buried the martyrs Eutychius, to whom Pope Damasus dedicated a poem, and Sebastian, whose tomb was later arranged with a crypt with a double staircase to the left of the basilica. The presence of these two martyrs was certainly the cause of the development of the cemetery in the 3rd and 4th centuries, and the cult paid to St Sebastian led to the designation of both the cemetery and the basilica by his name.