Constantine/Cyril (b. ca. 836, Salonika [Byzantine Empire], Greece; d. February 14, 869, Rome [Papal States], Italy) — Byzantine missionary, diplomat, scholar, and theologian. At the request of Prince Rostislav of *Greater Moravia, Constantine, known as “the Philosopher,” together with his brother Methodius undertook missionary work to spread Christianity among the Slavs of Greater Moravia between the years 863 and 867. Some writers (Stepan Pap, Gorazd A. Timkovic) also believe that the brothers brought Christianity to the Slavs of the Upper Tisza region, including present-day *Subcarpathian Rus’ and the *Presov Region. Before their arrival among the Moravian and Upper Tisza Slavs, the brothers created a new alphabet (the *Glagolitic) and began to translate into Slavonic a wide variety of evangelical and liturgical texts and writings of the church fathers, as well as their own works (Proglas do Evangeliia, Kanon (himn) Dmitriiu Solunskomu, Slovo na perenesennia moshchei Klimenta papi Rimskoho). As a result of such activity, they succeeded in raising Slavonic to the level of a liturgical language alongside Latin, Greek, and Hebrew. Their work in Greater Moravia was opposed, however, by Roman-rite priests from neighboring Bavaria, who refused to recognize the canonicity of Slavonic as a liturgical language. In an effort to resolve this dispute, Constantine and Methodius traveled to Rome in 867 to receive the support of Pope Adrian II. During his stay in Rome Constantine became a monk, adopting the name Cyril. He died soon after and was later canonized as St. Cyril. For their proselytizing of Christianity, Constantine/Cyril and Methodius have come to be known as the Apostles to the Slavs.
Bibliography: Frantisek Pastrnek, Dejiny slovanskych apostolu Cyrilla a Methoda s rozborem a otiskem hlavnich pramenu (Prague, 1902); F. Grivec, Konstantin und Metod, Lehrer der Slawen (Wiesbaden, 1960); Francis Dvornik, Byzantine Missions Among the Slavs: SS. Constantine-Cyril and Methodius (New Brunswick, N.J., 1970); Tadeusz Lehr-Splawinski, Konstantin i Metody (Warsaw, 1967); Emil Georgiev, Kiril i Metodii: istinatana suzdatelite na bulgarskata i slavianska pismenost (Sofia, 1969); Gorazd Andrej Timkovic, “Svaty Cyril (†869) bol katanskym episkopom,” Krasnobrodsky zbornik, I, 1-2 (Presov, 1996), pp. 53-90; D. Vozdvizhenskii, “Velikomoravskaia missiia Konstantina (Kirilla) i Mefodiia i problema ikh slavianskikh (podkarpatorusinskikh) rodstvennykh kornei,” Khrystyians’ka rodyna, No. 8  (Uzhhorod), May 15-31, 2000, pp. 6-11.
Entry courtesy of Encyclopedia of Rusyn History and Culture.