Cyril, or, according to his baptismal name, Constantine, and Methodius his brother, must be reckoned among the benefactors of mankind; for it was they who procured for the Slavic nations, so early as the ninth century, the inestimable privilege of reading the Holy Scriptures in a language familiar to their ears and minds; whilst the sacred volume yet remained, for centuries after, inaccessible to all the other European Christians, the exclusive property of the priesthood. They were born in Thessalonica, in the early part of the ninth century, of a noble family; it does not appear whether of Greek or of Slavic extraction. Macedonia, of which province Thessalonica was in the times of the Romans the capital, was inhabited by many Slavi at a very early period. Constantine, who obtained by his learning and abilities the surname of the Philosopher, could have learned Slavic here, even without belonging to the Slavic nation. As a flourishing commercial city, this place was peculiarly favourable for learning languages; and it was probably here too, that Constantine learned Armenian; for the introduction of several Armenian letters into the Slavic alphabet seems to prove, that this language was not unknown to him. When grown up, his parents sent him to Byzantium, where he entered the clerical profession. It is reported that there came ambassadors from the Khazares, a Hunnic-Tartaric tribe, to the emperor Michael, to ask for a teacher in Christianity. On the recommendation of Ignatius, Constantine was chosen for this mission, as being particularly qualified by his eloquence and piety. On the road he stopped for some time in Cherson on the Dnieper, where he learned the Khazaric language. The empire of the Khazares extended from the Volga and the Caspian Sea, across the Caucasian isthmus and the peninsula of Taurida, as far as to Moldavia and Walachia. Several Slavic tribes were tributary to them; but about the middle of the ninth century, at the time of Cyril's mission, their power began to decline; their vassals became their enemies, and gradually their conquerors; until towards the end of the tenth and at the beginning of the eleventh century, their empire became entirely extinct.[12] Constantine converted and baptized their Khan, whose example was followed by a great part of the nation. It was probably after he had returned from this mission, that Cyril went to convert the Bulgarians. At this time, or just before, according to Dobrovsky's opinion, he invented the Slavic letters, and translated the Gospels, during his stay in Byzantium. This however is nothing more than an hypothesis, against which other hypotheses have been started by other scholars. Between A.D. 861 and 863, there came another embassy to the emperor from the Moravian prince Rostislav, who asked for a teacher, not only to instruct his subjects in Christianity more perfectly than it had been done before, but also to teach them _to read_. Most of the Moravians were already baptized.