The various modes of worship which prevailed… were all considered by the people, as equally true; by the philosopher, as equally false; and by the magistrate, as equally useful. And thus toleration produced not only mutual indulgence, but even religious concord.
The superstition of the people was not imbittered by any mixture of theological rancor; nor was it confined by the chains of any speculative system. The devout polytheist, though fondly attached to his national rites, admitted with implicit faith the different religions of the earth. Fear, gratitude, and curiosity, a dream or an omen, a singular disorder, or a distant journey, perpetually disposed him to multiply the articles of his belief, and to enlarge the list of his protectors. The thin texture of the Pagan mythology was interwoven with various but not discordant materials. As soon as it was allowed that sages and heroes, who had lived or who had died for the benefit of their country, were exalted to a state of power and immortality, it was universally confessed, that they deserved, if not the adoration, at least the reverence, of all mankind. The deities of a thousand groves and a thousand streams possessed, in peace, their local and respective influence; nor could the Romans who deprecated the wrath of the Tiber, deride the Egyptian who presented his offering to the beneficent genius of the Nile. The visible powers of nature, the planets, and the elements were the same throughout the universe.
Gibbon, The Decline and Fall of the Roman Empire
Originally written about ancient Rome, although just as applicable to modern Japan.