While this, then, was the position of the bishops in relation to the presbyters, they at first considered themselves as standing on a footing of equality in relation to each other. But as certain of the presbyters in their as semblies had acquired a priority of rank over the others, it gradually came about in the same way that the bishops of the chief cities (Jerusalem, Antioch, Corinth, Alexandria, Constantinople, Rome) obtained a similar precedence among the bishops and received the title of metropolitan bishops; and very early in the history of Christianity we find the Bishop of Rome claiming to be the head of the Church as the true successor of Peter, whom Christ Himself had pronounced to be the rock on which he would build his Church. Roman Catholic writers found this supremacy of Peter upon the evidence of Scriptures, upon the a priori argument of the necessity of one supreme head both in the matter of government and the preservation .of the integ rity of doctrine and upon the testimony of early ecclesiastical writers, who witness to the tradition of the universal supremacy of the Roman see.
After the transfer of the capital of the Roman empire to Constantinople, this city rapidly rose to ecclesiastical importance and became a metropolitan see. Its bishops made claim to be the first see in the Christian world after Rome on account of the imperial dignity of the city, but this assumption was stoutly resisted by the apostolic sees of the East, whom Rome always sustained against Constan tinople's claim. After the Greek schism, Con stantinople assumed the primacy of the Greek Church.
The practice of solemnly investing bishops with their offices dates from the 7th century. Already in the 5th century the Popes had begun to send to the newly elected metropolitan bish ops (now called archbishops) the a kind of official mantle worn by archbishops, as a token of their sanction of the choice. Two centuries later it became the custom to conse crate bishops by investing them with the ring and crosier, the former as a token of marriage with the Church, the latter as a symbol of the pastoral office. Since this investiture was what :pee validity to the election Of the bishops, it the source of long continued contests between the Popes and the temporal sovereigns in the Middle Ages. The influential position which the bishops occupied in the state caused the temporal rulers to be desirous of keeping the right of investiture in their own hands, while the Popes with equal determination claimed the right for themselves. The contest was most bitter between the Popes and the emperors of the Romans, as they were called. It began in
the 11th century, but was not settled till 1122, then it was agreed in the concordat of Worms between Pope Calixtus II and the Emperor Henry V that the election of bishops should take place according to the laws of the under the direction of the Emperor, and that the spiritual investiture (with ring and crosier) should remain in the hands of the Pope, while the bishops were to be invested with the tem poral rights of their office by the Emperor. This is still the fundamental law of the Roman Catholic Church with regard to investiture. The election to a bishopric is for the most part in the hands of the dean and chapter of the cathedral of the diocese; but in some cases it is a right of the territorial sovereign. In any case papal confirmation is requisite before the appointment is complete. Roman Catholic bishops in England are appointed exclusively by the Pope.
When the system of the ecclesiastical rule was matured, the almost absolute authority exercised by bishops over the clergy of their dioceses; their intervention in the secular con cerns of the governments, to which they soon rendered themselves necessary by their superior information and their elevated rank; the ad ministration of the Church revenues; and their extensive ecclesiastical as well as criminal diction, drew them into the vortex of secular affairs, sometimes at spiritual expense. Still, it continued to he the bishop's duty to teach and preach in his own diocese, to watch purity of doctrine, to see that the people were provided with the sacraments, to visit the churches in his diocese, etc. The most dis tinctive functions of their spiritual office re mained as they still are, the ordination of the clergy, the consecration of other bishops, confirmation of youth, the consecration of churches, etc. In the Middle Ages they at tached to themselves subordinate or assistant bishops called' suffragans or coadjutors, who often had entrusted to them the performance of those functions which more especially con cerned the Church. The episcopal office being such as we have described it, the nobility, and even the sons of princes and kings, strove to obtain a dignity which was as honorable as it was profitable, and was not deemed incom patible with festivities and luxurious enjoy *lents. The splendid establishments which they were able to maintain from the large reve nues derived chiefly from rich donations to their churches by pious devotees, gave, to the bishops of Germany particularly, a high de gree of dignity. They became princes of the empire, and their influence on public affairs was highly important.