Fractio Panis

'Fractio Panis' fresco at the catacomb of Priscilla in Rome (2nd Cent AD)

Fractio Panis (Latin: Breaking of Bread) is the name given to a fresco in the Greek Chapel in the Catacomb of Priscilla, situated on the Via Salaria Nova in Rome. The fresco depicts seven persons at a table, six men and a woman. Like the whole of the decorations of the chapel, the fresco dates from the first half of the 2nd century. This is the earliest depiction of the way a Mass was celebrated in the first centuries. By chance this particular fresco, having been covered by a thick crust of stalactites, escaped the notice of the early explorers of the catacombs. In 1893, Jesuit art historian Joseph Wilpert, one of a band of young scholars, arrived at the conclusion that the roof and arches of this chapel were decorated with frescoes. Chemical reagents were used to remove the crust which covered the surface, and by the patient care of Wilpert this delicate operation was attended with complete success.
The earlier origin of the Mass was called ‘Breaking of Bread’ or Fractio Panis, as Christians gathered underground to celebrate, to sing hymns, to pray and share their wealth with the poor of their community. This was done mainly in catacombs, for fear that the Christians would be arrested if found by the Romans and other antagonists. 

One of the most meaningful parts of the Mass is just before communion, when the priest breaks the host, then shows it to the people as he says “Behold the Lamb of God....” It is a re-enactment of what Jesus did at the Last Supper when He gave the bread to the apostles, symbolic of His Body, and likewise the wine, symbolic of His Precious Blood.