For it very soon was apparent that the political unity which had been established over so great a geographical surface was the forerunner of intellectual, and therefore religious unity. Polytheism became practically inconsistent with the Roman empire, and a tendency arose for the introduction of some form of monotheism. Apart from the operations of Reason, it is clear that the recognition by so many nations of one emperor must soon be followed by the acknowledgment of one God. There is a disposition to uniformity among people who are associated by a common political bond. Moreover, the rivalries of a hundred priesthoods imparted to polytheism an intrinsic weakness; but monotheism implies centralization, an organized hierarchy, and therefore concentration of power. The different interests and collisions of multitudinous forms of religion sapped individual faith; a diffusion of practical atheism, manifested by a total indifference to all ceremonies, except so far as they were shows, was the result, the whole community falling into an unbelieving and godless state. The form of superstition through which the national mind had passed was essentially founded upon the recognition of an incessant intervention of many divinities determining human affairs; but such a faith became extinct by degrees among the educated. How was it possible that human reason should deal otherwise with all the contradictions and absurdities of a thousand indigenous and imported deities, each asserting his inconsistent pretensions. A god who in his native grove or temple has been paramount and unquestioned, sinks into insignificance when he is brought into a crowd of compeers. In this respect there is no difference between gods and men. Great cities are great levellers of both. He who has stood forth in undue proportions in the solitude of the country, sinks out of observation in the solitude of a crowd. [Sidenote: Roman philosophy.] [Sidenote: Varro. Lucretius.] [Sidenote: Cicero.]