The ultimate responsibility for this disaster is generally im puted to the political adventurers who dismembered the empire in 1204. It may indeed be said that at that time the Byzantine State seemed already stricken with paralysis and verging on dis solution, and it was menaced by the re-arisen power of Bulgaria. But more than once before (in the 7th century and in the 11th) it had recovered its strength when it was weak and in dire peril ; and, considering what the emperors of Nicaea and Michael VIII. accomplished, it seems probable that, if there had been no Fourth Crusade, it might have so revived and consolidated its forces in the course of the 13th century, as to be able to cope successfully with the first advances of the Ottomans. The true statement is that the Fourth Crusade was only an incident (not in itself de cisive) in a world-movement which doomed the Eastern empire to extinction—namely, the eastward movement of western Europe which began in the 11th century with the rise of the Normans and the First Crusade. Henceforward the empire was a middle State, pressed between expanding forces on the east and on the west, and its ultimate disappearance was inevitable.
In making the State Christian, Constantine made the Church a State institution, and therefore under imperial control. Caesaro papism was the logical consequence. The sacerdotium was united with the imperium in the person of the monarch as in the pagan State. The Church acquiesced, and yet did not acquiesce, in this theory. When a heretical emperor sought to impose his views, champions of ecclesiastical freedom never failed to come forward. At the very beginning Athanasius fought for the independence of the Church against the emperor Constantius. But the political principle which Constantine had taken for granted, and which was an indispensable condition of his adoption of Christianity, was fully recognized under Theodosius I., and, notwithstanding pro tests from time to time, was permanent. It is significant that Constantinople, which had become a second Rome politically, with its senate and capitol, became then a second Rome eccle siastically, and that the elevation of the see of Constantinople to patriarchal rank next to the Roman see was due to Theodosius (381), who gave a permanent form to the dualism of the empire. The patriarch became a State minister for religion. The character of the Church as a State institution is expressed above all in the synods. The general councils are not only summoned by the em peror, but are presided over by him or by his lay deputies. The order of the proceedings is modelled on that of the senate. The emperor or his representative not only keeps order but conducts the deliberations and intervenes in the theological debates. It has been erroneously thought that at the Council of Chalcedon (451) the legate of Pope Leo presided ; but the acts of that assembly teach us otherwise ; the privilege which the Roman legates pos sessed was that of voting first (the right of the princeps senatus).
The first general council at which a churchman presided was the seventh (at Nicaea, 787), at which the emperor (or empress) deputed, not a layman, but the patriarch Tarasius to preside. The resolutions of these ecclesiastical State-councils did not become the law of the empire till they were confirmed by imperial edicts. The emperors, in their capacity as heads of the Church, did not confine themselves to controlling it by controlling the councils. They soon began to issue edicts dealing with theology, by virtue of their own authority. It has been said that the council of Chal cedon closed an epoch of "parliamentary constitutionalism"; a general council was not summoned again for more than ioo years, though the empire during that period was seethirtg with religious disunion and unrest. The usurper Basiliscus in his short reign set an example which his successors were not slow to follow. He is sued an edict quashing the decision of Chalcedon. Zeno's Henoti kon issued a few years later was the second and more fa mous example of a method which Justinian largely used, and of which the Ecthesis of Heraclius, the Type of Constans II. and the iconoclastic edicts of Leo III. are well-known instances. It was a question of political expediency (determined by the circum stances, the intensity and nature of the opposition, etc.) whether an emperor supported his policy or not by an ecclesiastical council. The emperor was always able to control the election of the patriarch, and through him he directed the Church. Sometimes emperor and patriarch collided ; but in general the patriarchs were docile instruments, and when they were refractory they could be deposed. There were several means of resistance open to a patriarch, though he rarely availed himself of them. His par ticipation in the ceremony of coronation was indispensable, and he could refuse to crown a new emperor except on certain condi tions, and thus dictate a policy (instances in 812, Michael I.; 969, John Zimisces). There was the power of excommunication (Leo VI. was excommunicated on account of his fourth marriage). Another means of resistance for the Church was to invoke the sup port of the bishop of Rome, who embodied the principle of eccle siastical independence and whose see admittedly enjoyed prece dence and primacy over all the sees in Christendom. Up to the end of the 8th century he was a subject of the emperor, and some emperors exerted their ecclesiastical control over Rome by drastic measures (Justinian and Constans II.). But after the conquest of Italy by Charles the Great, the pope was outside the Byzantine domination; after the coronation of Charles in Boo he was asso ciated with a rival empire; and when ecclesiastical controversies arose in the East, the party in opposition was always ready to appeal to him as the highest authority in Christendom. Under the iconoclastic emperors the image-worshippers looked to him as the guardian of orthodoxy.