Saint Cyril and Saint Methodius, two learned and educated Greek Byzantine brothers from Thessalonica, well experienced in missionary work, received an order by the Byzantine emperor Michael III to go to the Slav country of Great Moravia and spread the Christian faith in their native Slavic language. In this, the Byzantine ruler wanted to please the Moravian ruler Prince Rastislav who had requested such missionaries having probably heard that “all people from Thessalonica speak pure Slavic” and would therefore be fit to spread the word of Christ to his population in an understandable language for them, since his people could speak neither Greek nor Latin. So, the brothers set off on a long and uncertain journey at the end of 863 AD or beginning of 894 AD. They took along a number of their pupils who spoke the Slavic language and also some basic liturgical books translated into Slavic. Their stay in Great Moravia was hard and strenuous – the German priests they found there (Prince Rastislav’s state was under Roman church administration) were full of animosity towards the brothers: they often complained to the Pope about their missionary work, so that Cyril and Methodius even had to go to Rome to defend themselves against accusations of heresy. After many such troubles, Pope Hadrian II finally allowed holding liturgy in Slavic. Cyril soon died (869AD) and was buried in Rome in the Church of St Clement of Rome, while Methodius and his pupils returned to Great Moravia where Methodius became the archbishop of the Moravian diocese. Nevertheless, he and his pupils continued to be relentlessly persecuted by German priests. When Methodius died in 885 AD his pupils were forced to withdraw to the south of Great Moravia where the South Slavic peoples lived. The West Slavic peoples who were under the jurisdiction of the West Roman Church soon abandoned the liturgical practices in Slavic, disregard the use of Slavic alphabet and returned to the use of Latin, as before. The South Slavs, however, accepted the pupils of the two Thessalonica brothers along with the use of the Slavic language in liturgy and the Slavic alphabet, upholding to this day the great work and heritage of Cyril and Methodius.