It is hardly necessary to state that a great religious conquest can be explained only on moral grounds.
Whatever part must be ascribed to the instinct of imitation and the contagion of example, in the last analysis we are always face to face with a series of individual conversions. The mysterious affinity of minds is as much due to reflection as to the continued and almost unconscious influence of confused aspirations that produce faith. The obscure gestation of a new ideal is accomplished with pangs of anguish. Violent struggles must have disturbed the souls of the masses when they were torn away from their old ancestral religions, or more often from indifference, by those exacting gods who demanded a surrender of the entire person, a devotion in the etymological meaning of the word. The consecration to Isis of the hero of Apuleius was the result of a call, of an appeal, by the goddess who wanted the neophyte to enlist in her sacred militia.[[7]]
If it is true that every conversion involves a psychological crisis, a transformation of the intimate personality of the individual, this is especially true of the propagation of the Oriental religions. Born outside of the narrow limits of the Roman city, they grew up frequently in hostility to it, and were international, consequently individual. The bond that formerly kept devotion centered upon the city or the tribe, upon the gens or the family, was broken. In place of the ancient social groups communities of initiates came into existence, who considered themselves brothers no matter where they came from.[[8]] A god, conceived of as being universal, received every mortal as his child. Whenever these religions had any relation to the state they were no longer called upon to support old municipal or social institutions, but to lend their strength to the
authority of a sovereign regarded as the eternal lord of the whole world jointly with God himself. In the circles of the mystics, Asiatics mingled with Romans, and slaves with high functionaries. The adoption of the same faith made the poor freedman the equal and sometimes the superior, of the decurion and the clarissimus. All submitted to the same rules and participated in the same festivities, in which the distinctions of an aristocratic society and the differences of blood and country were obliterated. The distinctions of race and nationality, of magistrate and father of a family, of patrician and plebeian, of citizen and foreigner, were abolished; all were but men, and in order to recruit members, those religions worked upon man and his character.
In order to gain the masses and the cream of Roman society (as they did for a whole century) the barbarian mysteries had to possess a powerful charm, they had to satisfy the deep wants of the human soul, and their strength had to be superior to that of the ancient Greco-Roman religion. To explain the reasons for their victory we must try to reveal the nature of this superiority—I mean their superiority in the struggle, without assuming innate superiority.
I believe that we can define it by stating that those religions gave greater satisfaction first, to the senses and passions, secondly, to the intelligence, finally, and above all, to the conscience.
In the first place, they appealed more strongly to the senses. This was their most obvious feature, and it has been pointed out more often than any other. Perhaps there never was a religion so cold and prosaic as the Roman. Being subordinated to politics, it sought,
above all, to secure the protection of the gods for the state and to avert the effects of their malevolence by the strict execution of appropriate practices. It entered into a contract with the celestial powers from which mutual obligations arose: sacrifices on one side, favors on the other. The pontiffs, who were also magistrates, regulated the religious practices with the exact precision of jurists;[[9]] as far as we know the prayers were all couched in formulas as dry and verbose as notarial instruments. The liturgy reminds one of the ancient civil law on account of the minuteness of its prescriptions. This religion looked suspiciously at the abandonment of the soul to the ecstasies of devotion. It repressed, by force if necessary, the exuberant manifestations of too ardent faith and everything that was not in keeping with the grave dignity befitting the relations of a civis Romanus with a god. The Jews had the same scrupulous respect as the Romans for a religious code and formulas of the past, "but in spite of their dry and minute practices, the legalism of the Pharisees stirred the heart more strongly than did Roman formalism."[[10]]
Lacking the recognized authority of official creeds, the Oriental religions had to appeal to the passions of the individual in order to make proselytes. They attracted men first by the disturbing seductiveness of their mysteries, where terror and hope were evoked in turns, and charmed them by the pomp of their festivities and the magnificence of their processions. Men were fascinated by the languishing songs and intoxicating melodies. Above all these religions taught men how to reach that blissful state in which the soul was freed from the tyranny of the body and of suffering,
and lost itself in raptures. They led to ecstasy either by means of nervous tension resulting from continued maceration and fervent contemplation or by more material means like the stimulation of vertiginous dances and dizzy music, or even by the absorption of fermented liquors after a long abstinence,[[11]] as in the case of the priests of the Great Mother. In mysticism it is easy to descend from the sublime to the vile.