Two brothers invented an alphabet so Slavs could pray
Constantine and Michael of Thessalonica—remembered as Cyril and Methodius—answered Great Moravia's call in 862 with a script fitted to Slavic speech. Glagolitic came first; its descendant Cyrillic still carries liturgies and literatures across much of the Slavic world.
Cyril (born Constantine, 826–869) and Methodius (born Michael, 815–885) were Byzantine missionary brothers. Credited with devising Glagolitic, the first alphabet for Old Church Slavonic, they are "equals-to-the-apostles" in Orthodoxy; Pope Leo XIII extended their feast to the Catholic Church in 1880, and John Paul II declared them co-patrons of Europe in 1980. Ethnic origins—Slavic, Greek, or both—remain debated. Their father Leo held the rank of droungarios in the Byzantine theme of Thessalonica, and their mother was called Maria.
Raised in Thessalonica after losing their father when Cyril was fourteen, they gained a protector in the powerful minister Theoktistos. About 860, Emperor Michael III and Patriarch Photius sent Cyril to the Khazars. Methodius rose in administration and became an abbot. In 862 Prince Rastislav of Great Moravia asked for teachers who could evangelize in Slavic—likely seeking political independence from Latin clergy as much as sermons. Rastislav's own letter, though, says his subjects had already abandoned paganism, so the brothers were not Moravia's first Christian teachers.
For that mission the brothers designed Glagolitic to match Slavic sounds; many languages still use Cyrillic, its later descendant. They also wrote the first Slavic civil code for Great Moravia. Church Slavonic, grown from Old Church Slavonic, remains the liturgical tongue in many Orthodox and some Eastern Catholic churches. Clashes with Frankish missionaries sent them to Rome, where they arrived in 868 carrying relics of Pope Clement I; Pope Adrian II approved their Slavic liturgy and ordained Methodius a priest. Cyril became a monk and died in Rome on 14 February 869. Methodius, named Archbishop of Sirmium, was later deposed by East Frankish bishops and confined for two and a half years, possibly at Reichenau Abbey, until Pope John VIII won his release in 873.
Source: Cyril and Methodius
