Outside the domain of the “Pseudomorphosis,” on the contrary, the cavern-feeling was free to develop its own form-language, and here therefore it is _the definite roof that is emphasized_ (whereas in the other domain the protest against the Classical feeling led merely to the development of an _interior_). When and where the various possibilities of dome, cupola, barrel-vaulting, rib-vaulting, came into existence as technical methods is, as we have already said, a matter of no significance. What is of decisive importance is the fact that about the time of Christ’s birth and the rise of the new world-feeling, the new space-symbolism must have begun to make use of these forms and to develop them further in expressiveness. It will very likely come to be shown that the fire-temples and synagogues of Mesopotamia (and possibly also the temples of Athtar in Southern Arabia) were originally cupola- buildings.[261] Certainly the pagan marna-temple at Gaza was so, and long before Pauline Christianity took possession of these forms under Constantine, builders of Eastern origin had introduced them, as novelties to please the taste of the Megalopolitans, into all parts of the Roman Empire. In Rome itself, Apollodorus of Damascus was employed under Trajan for the vaulting of the temple of “Venus and Rome,” and the domed chambers of the Baths of Caracalla and the so-called “Minerva Medica” of Gallienus’s time were built by Syrians. But the masterpiece, _the earliest of all Mosques_, is the Pantheon as rebuilt by Hadrian. Here, without a doubt, the emperor was imitating, for the satisfaction of his own taste, cult-buildings that he had seen in the East.[262]