The Relation of Spiritual to Secular Authority. In the early days of Roman Christianity, the emperor had been recognized as head of both state and church. The right of the church to impose spiritual penalties for immoral acts was acknowledged, however, and was exercised even upon the emperors. As the church grew in power and its authority gravitated into the hands of the pope, the right to excommunicate disobedient members became a valuable weapon.
The consequences of this penalty were extended into temporal affairs, and the doctrine was developed that an excommunicated ruler was no longer entitled to the allegiance of his subjects. The feudal theory of the state proved useful to the church on this point.
As early as the ninth century, the pope excommunicated the King of Lorraine, who had divorced his wife and married his mistress, Although the king was supported by his brother, the emperor, and by many powerful bishops, the pope prevailed, mainly because the moral issue involved was clear, In this contest, the pope not only strengthened his position in the church, but also put forward claims to authority that encroached seriously on temporal jurisdiction.
When the alliance of church and state was consummated under Charlemagne, and even when the Holy Roman Empire was established under Otto, no attempt was made to define the respective powers of the emperor and pope. They were expected to rule jointly and harmoniously in a universal church-state.
The feudal political conditions of the period, however, made it impossible for the emperor to exercise real headship, while the organization of the church on the Roman imperial model tended to concentrate authority in the hands of the pope. The increasing wealth of the church, especially in land, made it necessary for church officials to take an active part in politics.
Accordingly, the temptation to extend their activities into the secular field was too strong to be resisted by the able men who governed the church. The ruler who was strong enough to bring others under his control turned to the popes to get a sanction for claiming universal power. In forming the empire, therefore, the papal claims to universal power were also fostered. Ultimately two authorities, the emperor and pope, were left face to face.
In the eleventh century, the rival powers of the emperor and the pope were brought to a distinct clash. To prevent the corrupt practice of purchasing church offices, and with the deliberate purpose of increasing his authority and independence, Pope Gregory VII decreed that no ecclesiastic should be invested with the symbols of office by a secular ruler, under penalty of excommunication.
This decree transferred to the pope the selection of men for important church offices formerly exercised by the temporal rulers; and, because of the large landed estates of the church, diverted valuable feudal privileges from the secular to the ecclesiastical powers.
The emperor, Henry IV, refusing to obey this decree, called a council of subservient church officials and declared the pope deposed. The pope in turn excommunicated the emperor and absolved his subjects from their oaths of allegiance.
Thus began a contest which lasted, with numerous compromises and fluctuations of power, for two centuries. Out of this struggle, the pope ultimately emerged victorious as the unquestioned head of western Christendom, while the empire fell into feudal fragments and free cities. The office of the emperor became merely a name.
The contest that the emperors had failed to win was taken up later by the kings of the rising national states. The papacy reached the height of its temporal power in the thirteenth century, under Innocent III. He was strong enough to decide disputed successions to the empire, to compel the French king to take back his divorced wife, to require the English king to acknowledge himself a vassal of the pope and to hold the Christian kingdoms in Spain as papal dependencies. By the fourteenth century, however, the kings had consolidated their royal power, and the feudal independence and authority of the nobles, upon whom the popes had largely depended in their contests, had been decidedly reduced.
The process of royal centralization was particularly successful in France so that when Pope Boniface tried to prevent the French king from taxing ecclesiastical property, the king was able to defy the pope, and later transfer the papacy from Rome to Avignon bringing it under French control. The Great Schism, which followed, further weakened the position of the pope, who found it increasingly difficult to exercise any important temporal powers in the growing national states of France, Spain, and England.
In the German and Italian fragments of the empire, a show of political authority was retained. The rise and decline of the secular power of the popes, and their contests with emperors and kings were the issues about which medieval political theory revolved.