Little is known about Sts. Martinian and Processus, but their altar features a dramatic mosaic of their martyrdom. St. Peter’s Basilica in Rome might be where the chief of the Apostles is buried and where his successor often celebrates Mass. But it also honors two men who had guarded St. Peter in prison.
All that is known about Sts. Martinian and Processus is that they were originally buried in an apostolic-era cemetery along the Via Aurelia. Their dates of birth and death are unknown.
According to the Catholic Encyclopedia, Pope Paschal I (817-24) transferred the bones of the two martyrs to a chapel in the old basilica of St. Peter. Today, their relics lie in an urn under the altar dedicated to them in St. Peter’s, in the center of the north transept. Their feast is celebrated on July 2.
Butler’s Lives of the Saints tells us that Sts. Processus and Martinian were publicly venerated in Rome from at least the 4th century. It disputes the legend that they and 40 others were converted by Peter and Paul while in prison. But the story was adopted by the Roman Martyrology and Breviary, so it’s worth consideration. The legend tells of a flow of water miraculously springing from the rock to enable St. Pater to baptize the guards.
“The officer in charge, Paulinu, tried to persuade Processus and Martinian from their new faith, and afterwards subjected them to cruel tortures when they would not offer incense on the altar of Jupiter,” the Lives relates:
Their sufferings only wrung from them the words, “Blessed be the name of the Lord.” So they were slain with the sword. Whoever these two martyrs may actually have been, they were buried, it is said, by a woman called Lucina on her own property, near the second milestone on the Via Aurelia, and in the fourth century a basilica was built over their tomb, wherein St. Gregory the Great preached his thirty-second homily on their feast-day, in the course of which he said that at that place the sick were healed, the possessed were freed, and the forsworn were tormented.
A 2001 virtual tour of the basilica created by Our Sunday Visitor describes the altar dedicated to the two martyrs. The altar is “flanked by two superb antique yellow columns. The depiction of the martyrdom of the two saints was executed in 1737 by the able mosaicist Fabio Cristofari from the original painting, now in the Vatican Pinacoteca, by Jean de Boulogne known as ‘Valentin,’ one of the major French followers of Caravaggio, from whom he assimilated the expressive realism and the dramatic contrasts in light and shade, giving them his own interpretation.”
Louise Rice’s 1997 book The Altars and Altarpieces of New St. Peter’s describes this mosaic:
The saints are stretched out head-to-foot on a rack. One torturer turns a crank to increase the tension; another heats metal pokers in the coals; a third prepares to beat the martyrs with a rod. As though the brutality of these executioners defies pictorial expression, Valentin had hidden their faces from view, either turning them away or casting them in shadow. Several soldiers are in attendance, their presence a poignant reminder that the men on the rack were once their comrades; Processus and Martinian too were once soldiers of Caesar, but now they are soldiers of Christ. On the left, a veiled woman watches with a gentle and sorrowful expression; on the right a raised throne, a bearded man, wearing a toga suggestive of authority, clutches his right eye with one arm while pointing with the other toward a statue of Jupiter. Angels descend on clouds, bringing palms of martyrdom.
