In the symbols of the alchemists, the rosicrucians, the Lodges, etc., “we meet a language that has found acceptance among all occidental peoples in analogous form, not indeed a letter or word language, but a language nevertheless, a token or a symbol language of developed form, which is evident even in the rock temples of the so-called catacombs, once called latomies and loggie. The single images and symbols have something to say only to the person who understands this language. To the man who does not understand it, they say nothing and are not expected to say anything.” In reference to the symbol and image language, which was comprehensible only to the initiated, we think naturally of the ancient mysteries. The religious societies of the oldest Christians, in the centuries when Christianity belonged in the Roman Empire to the forbidden cults, found a possibility of existence before the law in the form of licensed societies, i.e., as guilds, burial unions, and corporations of all sorts. The primitive Christians were not the only forbidden sects that sought and found this recourse. Under the disguise of schools, trade unions, literary societies, and academies, there existed in the jurisdiction of the Roman Empire, and later inside of the world church, organizations that before the law were secular societies, but in the minds of the initiated were associations of a religious character. Within these associations there appeared very early a well developed system of symbols, which were adopted for the purpose of actually maintaining, through the concealment necessitated by circumstances, their unions and their implements and customs—symbols that they chose as cloaks and that in the circle of the initiated were explained and interpreted according to the teachings of their cult. Valuable monuments of this symbolism are preserved in the vast rock temples that are found in Egypt, Syria, Asia Minor, Sicily, and the Apennine peninsula, in Greece, France, and on the Rhine, and these vaults, which in part also served the early Christians as places of worship, show in their images and records and in their architectural form so close a resemblance that they must be acknowledged as the characteristic of a great religious cult extending over many lands, which has had consistent traditions for the use of such symbols and for the production of these structures.