Catacomba dei Santi Marco e Marcelliano, Ancient catacomb complex near Via Ardeatina in Rome, Italy.

The Catacomba dei Santi Marco e Marcelliano lies between the Via Appia Antica and the Via Ardeatina in Rome's Ardeatino district, one of the burial areas of the Callistian complex. Its core is a central region grown from a stairway built after 331, with architecturally complex cubicula decorated in paint and marble, including the mid-4th-century "cubicolo delle colonne" and the later "cubicolo dei dodici apostoli". Other regions date to the second half of the 4th century, one rising on three floors.

The cemetery was first called after Basileus, the landowner who had it dug; after the Edict of Milan in 313 it took the names of the martyrs Mark and Marcellian, killed with Pope Gaius in 296. Pope Damasus I chose a tomb here for himself, his mother Laurentia and his sister Irene. Antonio Bosio explored it in 1596, Giovanni Battista de Rossi misidentified it as the cemetery of Balbina in 1868, and Joseph Wilpert's excavations of 1902-1905 confirmed the identification.

The name recorded in ancient sources was "cemetery of Basileus at Saint Mark and Marcellian", pairing the landowner Basileus with the two martyrs killed with Pope Gaius in 296. The cemetery was also called after Pope Damasus, who chose a tomb here for himself, his mother Lorenza and his sister Irene.

The catacomb lies between the Via Appia Antica and the Via Ardeatina in the Ardeatino district, near the vicolo delle Sette Chiese. The above-ground remains were found beneath the courtyard of the Istituto San Tarcisio on the Via Appia Antica, now run by the Salesians. The cemetery develops from a central region reached by a staircase built after 331, with one branch rising on three floors.

A four-column crypt with paintings serves as a key identifying feature that helped archaeologists confirm the true identity of this underground site. This architectural detail sets it apart from other catacombs in the area.