Quibbles are even made, and discussions raised at last as to the question whether Father and Son are “of one substance” or only “of like substance”; whether the Holy Ghost proceeds from the Father and the Son, or from the Father only; and so on _ad infinitum_. It was largely in other countries than Judæa, and especially in Gaul, Rome, and Egypt, too, as I believe, that symbolism came to the aid of mysticism: that the cross, the tau, the labarum, the fish, the Alpha and Omega, and all the other early Christian emblems were evolved and perfected; and that the beginnings of Christian art took their first definite forms. Such forms were especially to a great extent evolved in the Roman catacombs. Christianity, being a universal, not a local or national, religion, has {009}adopted in its course many diverse elements from most varied sources. Originally, it would seem, the Christian pantheon was almost exclusively filled by the triune God, in his three developments or “persons,” as thus rigorously conceived by the Alexandrian intelligence. But from a very early time, if not from the first dawn of the Christian cult, it was customary to reverence the remains of those who had suffered for the faith, and perhaps even to invoke their aid with Christ and the Father. The Roman branch of the church, especially, accustomed to the Roman ancestor-worship and the Roman reverence for the Du Manes, had its chief places of prayer in the catacombs, where its dead were laid. Thus arose the practice of the invocation of saints, at whose graves or relics prayers were offered, both to the supreme deity and to the faithful dead themselves as intercessors with Christ and the Father. The early Christians, accustomed in their heathen stage to pay respect and even worship to the spirits of their deceased friends, could not immediately give up this pious custom after their conversion to the new creed, and so grafted it on to their adopted religion. Thus the subsidiary founders of Christianity, Paul, Peter, the Apostles, the Evangelists, the martyrs, the confessors, came to form, as it were, a subsidiary pantheon, and to rank to some extent almost as an inferior order of deities.