When the rising religion of the internal proletariat of the Hellenic World in its universal state was persecuted by the dominant minority, the Roman Imperial authorities were able to suppress the public practice of Christianity, but they failed to suppress Christianity itself: they merely drove it underground. The prohibition of Christian worship on the surface of pagan Rome stimulated the Christians to create for themselves a new Christian Rome in the Catacombs below the surface of the Campagna; and the City of the Catacombs eventually triumphed over the City of the Seven Hills. The Church rose again from the bowels of the earth in order to raise in the City of the Vatican a dome which towers at this day above the Capitol; and the early Latin peasant, who responded to the challenge of his physical environment by breaking in the intractable surface of the Campagna with his plough, was emulated by the latter-day Christian denizen of the Roman slums, who responded to the challenge from his human environment by visiting the Campagna in the secrecy of the night-watches in order to carve a labyrinthine subterranean world of his own out of the solid tufa. The monument of the Latin peasant’s feat is the Roman Empire; the monument of the Christian proletarian’s feat is the Roman Catholic Church.
A Study of History, Vol II, OUP, 1934