Catacomb of Saints Marcellinus and Peter on the Via Labicana This cemetery is at the third milestone on Via Labicana, near to an imperial villa belonging to Constantine.
"Christ with the book of the Gospels is seated between Peter and Paul. Below, the Lamb is standing in the centre on a hill, from which flow out the four symbolic rivers of Scripture. To the sides are the most venerated Martyrs, with their names: Gorgonius, Peter, Marcellinus, Tiburtius, all acclaiming the Lamb." (Christian Catacombs of Rome - Website)
"The historical and religious associations of this catacomb [the Catacomb of Saints Marcellinus and Peter] are summed up and illustrated in a beautiful picture representing the Savior with S. Paul on his right and S. Peter on his left: and, on a line below, the four martyrs who were buried in the cemetery, Gorgonius, Peter, Marcellinus, and Tiburtius, pointing with their right hands to the Divine Lamb on the mountain. The heads of the two apostles are particularly fine, and the shape of their beards most characteristic. This well-known fresco, preserved in cubiculum no. 25 of Bosio's plan, was discovered in 1851 by de Rossi, in a curious manner. (...)". (quote from the PD-old book: Pagan and Christian Rome, by Rodolfo Lanciani, 1892 - p.357)
