Cyril was a learned monk, who had been trained at the Court of Constantinople, and was well skilled in various languages. Taking the Greek alphabet as his basis, but altering its form, he invented a written language for the Slavonic race, into which he translated a liturgy, several books of the Bible, and some of the early Fathers.
The news of the conversion of the Bulgarians quickly came to the ears of Rostislav, for the great Bulgarian kingdom touched the eastern side of Moravia; and the recent alliance had brought the two peoples into closer intercourse. Unwelcome as Christianity had seemed to the Moravians, when presented to them as a demand of Frankish invaders, and taught in an unknown tongue, its lessons came with a very different force when urged by pious and peaceable monks, recommended by friendly kinsmen, and expounded in a language intelligible to the converts. Rostislav no doubt quickly perceived that the new teaching might form a valuable link in the alliance of the Slavs against their enemies. He appealed to the Emperor of the East to send Cyril and Methodius to Moravia; and, when they arrived at the town of Devina, Rostislav and his followers went out to welcome them; and after Cyril had retired from the mission, Methodius was recognised by the Pope as Archbishop of Moravia and Pannonia.
But troubles very soon began for the new-comers. The German party in Moravia were resentful at the introduction into the churches of what they considered a barbarous language; and they saw danger to their power, both in the adoption of a ritual which was understood by the people, and in the assertion of an episcopal authority which claimed to be independent of the German bishops. Nor was it only by foreigners that the influence of Cyril and Methodius was endangered; an opposition was roused even among the Moravians themselves. Svatopluk, the nephew and rival of Rostislav, seems to have accepted some kind of nominal Christianity, but unaccompanied by any change of life, or even by any great reverence for the externals of worship; and he opposed the new apostles of the Slavs with the greatest fierceness. The opposition of this ambitious prince no doubt arose at first from his desire to pose as the champion of the German party, who were undermining his uncle’s authority. According to one story he had already attempted to poison Rostislav, and having failed in that purpose he conspired with the Emperor Louis against him, made him prisoner, and sent him off to the Imperial Court to be tried. Louis threw Rostislav into prison, and put out his eyes. But Svatopluk, though he succeeded in seizing the Dukedom, did not long retain the confidence of the Emperor or the German party. He, in his turn, was deposed and thrown into prison.
Then the Moravians rose against the Franks, under a man named Slavomir, who, according to one story, was a pupil of Methodius. The Emperor thereupon set Svatopluk free, and sent him at the head of an army to suppress the new rising. Svatopluk betrayed his soldiers to his countrymen, destroyed the German army, and once more became Duke of Moravia. He now felt it impossible any longer to pose as the champion of the German party; and he had married the sister of Duke Bor̆ivoj, of Bohemia, in order to strengthen the alliance of the Slavs against the Franks. As a part of his new policy, he was forced, for a time, to encourage the movement of Methodius; and it was during this period that the archbishop or one of his followers converted and baptised Bor̆ivoj, and induced him to found two churches in memory of St. Clement of Rome, whose remains Cyril had discovered in his expedition to the Chazars.
There seems some difficulty in ascertaining how far the Slavonic ritual came into general use in Bohemia at this time. It is tolerably certain, on the one hand, that Methodius did not desire to oppose the authority of the Bishop of Regensburg, who claimed to be primate over the Bohemian Christians; and that bishop, like all the German prelates, was opposed to the spread of the Slavonic ritual. On the other hand, it is clear that, as Christianity grew in Bohemia, it connected itself with Slavonic traditions; and we find that in less than a century from this time the Bohemian congregations had adopted a Slavonic hymn as a necessary part of their ritual.
But, however slow the progress of Slavonic Christianity may have been in Bohemia, Methodius does not seem to have excited there that savage hostility which he continued to provoke in Moravia. Svatopluk and his courtiers were, no doubt, indignant at the higher morality preached by Methodius; and one of the claimants of the German Empire, with whom Svatopluk was alternately in alliance and enmity, resented extremely the authority claimed by Methodius over Pannonia as well as Moravia. But, in order to strengthen their position, the opponents of Methodius took advantage of his having come from Constantinople, to attack him as a rebel against the Pope, and a supporter of the Greek heresy of the Single Procession.
CYRIL AND METHODIUS, FROM THE WINDOW OF A CHURCH IN CAROLINEN-THAL.
The first of these charges was singularly inconsistent with the traditions of both the brothers, who led the mission to the Slavs. Cyril had been partially induced to go on his mission to the Chazars by the unfriendly relations which had arisen between him and the Patriarch of Constantinople. While in the Chersonesus he had discovered the bones of the Roman saint, Clement, who had died there; and he had ever since recognised this saint as the special patron of his mission to the Slavs. After Cyril and Methodius had established themselves in Moravia, they had applied to Rome for sanction to their work; and when they had been summoned to the Court of the Pope, in consequence of this application, Cyril had been so much attracted to the place that he had entered a Roman monastery, and had abandoned the mission, for the future, to Methodius. Methodius, on his part, seems to have been little inclined to resist authority, where no moral or religious principle was concerned. So in 879 he readily accepted the summons to appear before the Roman Synod, and easily convinced Pope John VIII. of his willingness to obey him. Methodius was equally happy in vindicating his orthodoxy in the matter of the Double Procession.