The Roman Church is founded upon three events: the apostolic preaching, the constancy of its martyrs, its position as the heir of Imperial Rome--a position early figured and represented in the persons of its bishops. All these things have their monument in the catacombs; which bear indisputable traces of the sojourn and the preaching of the Apostles, which are the earliest shrines of the Roman martyrs, and which preserve for us in the crypt in the cemetery of Callistus, set apart for the leaders of the Roman Church from Antheros to Eutychian (A.D. 235-275),[3] the veritable nucleus of papal domination. It was the successors of these men who were to fill the role left vacant by Constantine's departure for Byzantium; to be forced into a position of overlordship through the uncertainty of the emperor's government by lieutenants--first in Rome and then in Italy; to consolidate this power by constant accretions of Italian territory, and, finally, to acquire by spiritual conquest a universal suzerainty as real as that of the Roman emperor. If those who inscribed the proud words round the dome of S. Peter's had known that hidden in the catacombs there were frescoes representing Peter as the new Moses striking the rock from which flow forth the saving waters of Christ--the name _Petrus_ clearly written above him--even they must have thrilled with wonder and awe: the upholders of Petrine primacy could not have imagined or devised a parable of the first centuries better fitted to their hand. [3] The popes from the time of Zephyrinus, the predecessor of Callistus, to Miltiades, who lived on the eve of the "Peace," rest in this great cemetery. The burial-places of the first Christians in Rome were their only certain property. The law allowed to every corporation its _religiosus locus_, its God's acre, property seldom confiscated even in the worst hours of the great persecutions. It was thus that the Christians, though they never lived in the catacombs, came to regard them as retreats, as places where it was safe to meet for prayer, for mutual encouragement, even for the catechising of neophytes and children. Round them were their dead, their loved ones, nay, round them were their martyrs, the men and women who were to prove that "the blood of the martyrs is the seed of the Church"; whose heroic deaths had been witnessed by many; the memory of whose heroism was to prove almost as potent as ocular witness when their burial-places became the nuclei of the first Christian churches, and the abounding reverence felt for them inaugurated the Christian cult of the saints. [Illustration: A PROCESSION IN THE CATACOMB OF CALLISTUS The nucleus of the great catacomb on the Via Appia was formed by the crypts of Lucina and the _hypogaeum_ of the family of the _Caecilii_, both pagan and Christian members of which had their burial places on the Appian Way. S. Cecilia was buried here. See pages 42, 45, 46, 29.]