Religion and the State

The collapse of the Roman Empire in the West left the Christian church as the major source of trans-European political, cultural, and social unity, and thus Christianity learned to persevere without a meaningful state to depend upon. Indeed, the institutional church, with its authority increasingly centralized in the papacy and the episcopal and diocesan systems, superceded the state entirely, using a combination of spiritual suasion and socio-economic power to control the fragmented and decentralized lordlings who amounted to local strongmen under the feudal structure. Despite attempts on the part of certain dynasties to revive the imperial ideal and extend centralized political control—Charlemagne and his successors are especially noteworthy—the church alone managed to bridge the chronological period between late imperial Rome and emergent Europe.

Thus, the Christian church was left in an unusually powerful position in relation to state authority when consolidation of the social bonds of the feudal nobility, and with it political centralization, recommenced after the year 1000. On the one hand, the church's legal, judicial, and administrative system provided a ready model for temporal governance, and the class of literate clergy that it trained afforded a pool of staff for aspiring monarchic states. Yet on the other hand, the church's monopoly over the state of souls, justified by its claim to have inherited from the Petrine commission the keys determining entrance into heaven, translated into assertions of universal supremacy in all affairs, earthly as well as spiritual. Advocates of the pope's superior station proposed a "plenitude of power" (plenitudo potestatis) inhering in the office of the Roman bishop that permitted him, at least in cases of emergency, to exercise "two swords," that is, both corporeal and otherworldly forms of authority. If not quite amounting to theocratic government, the Roman church sought for itself a wide jurisdiction in determining the arrangement of secular rule.

This situation was reflected in the political ideas typical of medieval Europe. Such mainstream thinkers as John of Salisbury (1115 or 1120–1180) and St. Thomas Aquinas (1224–1274) viewed secular government as directed toward two goals, one natural, the other supernatural. The former involved the promotion of virtue and justice among subjects; this could be attained by any political society, whether Christian or pagan. The latter demanded the promotion and diffusion of the true religion of Rome; only a Christian ruler could achieve this goal, and only when guided by and deferential to the Roman church and its leaders.