No people mentioned in history ever attained to a high rank in the scale of civilization whose policy was founded on the systematic repression of religious opinions. Theological intolerance is the most serious of obstacles to intellectual progress. Among the great nations of antiquity, freedom in religious matters was generally conceded as a matter of right. Where invasions of that right occurred, they may almost invariably be traced to interference with the established government. The intimate connection of political and religious institutions in those times will readily account for occasional examples of apparent persecution. The most eminent Athenian statesmen not infrequently performed the functions of priest in the ceremonial of public worship. The title of Pontifex Maximus was one of the most honorable and coveted of the dignities of the Republic of Rome, and under the Empire it conferred additional distinction upon the attributes and the exercise of imperial power. Under that wise and politic dispensation, the gods of foreign countries were admitted into the national pantheon on an equal footing with the domestic divinities, and none could claim an excessive and undue pre-eminence in the national system. It was not until the Christians profaned the altars, and excited mutiny in the army, that their privileges were curtailed and their religious ceremonies interrupted. The conditions formerly prevailing were then revolutionized. Indulgence was followed by persecution. Persecution disclosed and produced tens of thousands of proselytes. The experience of the Christian sect suggested the perpetuation in its religious constitution of the incomparable political system of the empire, a measure which in the end contributed so largely to its success, its discipline, and its permanence. In no country subject to the authority of the Papacy were the effects of these advantages of imperial organization more apparent than in the Spanish Peninsula.