Yahya ibn Sargun ibn Mansur was born in Damascus around the middle of the 7th century, into a Christian Arab family. His father held a high position under the caliph — something like what we would today call “Minister of Finance.” John grew up alongside Prince Yazid, and later worked with his father in the same office. Eventually, however, both father and son withdrew from the court, probably because of the growing anti-Christian stance of Caliph Abd al-Malik.
Together with his brother Cosmas, who would later become bishop of Maiuma, John entered the monastic community of Mar Saba. Though reluctant, he accepted priestly ordination from Patriarch John V of Jerusalem, who, like other bishops, often called on John to serve as a preacher and writer, especially during the controversy over the use of icons.
Tradition says that John was 104 years old when he died. The Second Council of Nicaea (the seventh ecumenical council) later praised both his wisdom and his holiness, correcting the injustices he had suffered at the hands of the iconoclasts and the Byzantine court.
Because of the breadth of his knowledge and his many writings, John is considered one of the greatest theologians of the Eastern Church. Though Arab by birth, he fully embraced Byzantine culture and wrote in Greek.
Originally, his feast in the Roman calendar was on March 27, the date chosen when Pope Leo XIII declared him a Doctor of the Church in 1890. The newer calendar moved the celebration to December 4, the date observed by the Byzantine Church, since the exact day of his death is unknown, though it is thought to have been around December 4, 749.
