How did St. Cyril die?

Answer 1

St. Cyril died in February of 869 shortly after traveling to Rome to receive Pope Adrian's approval of the Slavonic liturgy (late 868). In "Life and Acts of Constantine", Clement of Ohrid, a contemporary, reports that St. Cyril (known as Constantine the Philosopher) had already "borne... ailments for a long time", but "fell ill" in Rome, took monastic vows, and died 50 days later. The same source records that Cyril was suffering from some ailment as early as 863, when he was told to prepare for the Moravian Mission. Michael III says to Cyril, "i know you are weary", to which Cyril responds that he is not just weary but ill (bolen). It seems Clement Ohridski is referring to the same illness when he describes the last days of Cyril's life. So this would suggest that Cyril died of a long term disease which he suffered from for over 5 years. There is no mention of how he contracted any disease, although the "Vita" does claim that he was poisoned by the Saracens while on a diplomatic assignment in Baghdad and miraculously survived (this would have been in the early 850s). He seems to have contracted the disease he died of while on the mission to the Khazars of the Black sea coast, since his appointment to the head of the Moravian mission seems to have occurred shortly after his return from the Khazar lands. The "Vita" does mention that Cyril was so thirsty he drank swamp water on the way back to Constntinople. He also dined with and was blessed by the Archbishop of Cherson who died the next day. He could have contracted a disease in either of these instances.