Europe and the Faith. Hilaire Belloc

a language which the cultured knew and used throughout the western or Latin part of the Empire to which he belonged; the title would not, therefore, seem to him alien any more than would be the Greek title of Presbyter—the name of the official priests acting under this monarchical head of the organization—or than would the Greek title Diaconos, which title was attached to an order, just below the priests, which was comprised of the inferior officials of the clerical body.

      He knew that this particular cult, like the innumerable others that were represented by the various sacred buildings of the city, had its mysteries, its solemn ritual, and so forth, in which these, the officials of its body, might alone engage, and which the mass of the local "Christians"—for such was their popular name—attended as a congregation. But he would further know that this scheme of worship differed wholly from any other of the many observances round it by a certain fixity of definition. The Catholic Church was not an opinion, nor a fashion, nor a philosophy; it was not a theory nor a habit; it was a clearly delineated body corporate based on numerous exact doctrines, extremely jealous of its unity and of its precise definitions, and filled, as was no other body of men at that time, with passionate conviction.