But a theoretical adherence of the mind to dogmas that satisfy it, does not suffice to convert it to a new religion. There must be motives of conduct and a basis for hope besides grounds for belief. The Persian dualism was not only a powerful metaphysical conception; it was also the foundation of a very efficacious system of ethics, and this was the chief agent in the success of the mysteries of Mithra during the second and third centuries in the Roman world then animated by unrealized aspirations for more perfect justice and holiness. A sentence of the Emperor Julian,[46] unfortunately too brief, tells us that Mithra subjected his worshipers to "commandments" ([Greek: entolai]) and rewarded faithful observance both in this world and in the next. The {155} importance attached by the Persians to their peculiar ethics and the rigor with which they observed its precepts, are perhaps the most striking features of their national character as manifested in history. They were a race of conquerors subject to a severe discipline, like the Romans, and like them they realized the necessity of discipline in the administration of a vast empire. Certain affinities between the two imperial nations connected them directly without the mediation of the Greek world. Mazdaism brought long awaited satisfaction to the old-time Roman desire for a practical religion that would subject the individual to a rule of conduct and contribute to the welfare of the state.[47] Mithra infused a new vigor into the paganism of the Occident by introducing the imperative ethics of Persia. Unhappily the text of the Mithraic decalogue has not been preserved and its principal commandments can be restored only by implication. Mithra, the ancient spirit of light, became the god of truth and justice in the religion of Zoroaster and retained that character in the Occident. He was the Mazdean Apollo, but while Hellenism, with a finer appreciation of beauty, developed the esthetic qualities in Apollo, the Persians, caring more for matters of conscience, emphasized the moral character in Mithra.[48] The Greeks, themselves little scrupulous in that respect, were struck by the abhorrence in which their Oriental neighbors held a lie. The Persians conceived of Ahriman as the embodiment of deceit. Mithra was always the god invoked as the guarantor of faith and protector of the inviolability of contracts. Absolute fidelity to his oath had to be a cardinal virtue {156} in the religion of a soldier, whose first act upon enlistment was to pledge obedience and devotion to the sovereign. This religion exalted loyalty and fidelity and undoubtedly tried to inspire a feeling similar to our modern idea of honor.