Saint John was born in the late 7th century, and is the most remarkable of the Greek writers of the 8th century.
His father was a civil authority who was Christian amid the Saracens of Damascus, whose caliph made him his minister.
This enlightened man found in the public square one day, amid a group of sad Christian captives, a priest of Italian origin who had been condemned to slavery; he ransomed him and assigned him to his young son to be his tutor.
Young John made extraordinary progress in grammar, dialectic, mathematics, music, poetry, astronomy, but above all in theology, the discipline imparting knowledge of God.
John became famous for his encyclopedic knowledge and theological method, later a source of inspiration to Saint Thomas Aquinas.
When his father died, the caliph made of him his principal counselor, his Grand Vizier.
Thus it was through Saint John Damascene that the advanced sciences made their apparition among the Arab Moslems, who had burnt the library of Alexandria in Egypt; it was not the Moslems who instructed the Christians, as was believed for some time in Europe.
Saint John vigorously opposed the ferocious Iconoclast persecution instigated by the Emperor of Constantinople, Leo the Isaurian.
He distinguished himself, with Saint Germain, Patriarch of Constantinople, in the defense of the veneration of sacred images.
The Emperor, irritated, himself conjured up a plot against him.
A letter was forged, signed with Saint John’s name, and addressed to himself, the Emperor of Constantinople, offering to deliver up the city of Damascus to him.
That letter was then transmitted by the Emperor to the Caliph of Damascus, advising him as a good neighbor should do, that he had a traitor for minister.
Although Saint John vigorously defended himself against the charge, he was condemned by the Caliph to have his right hand cut off.
The severed hand, by order of the Caliph, was attached to a post in a public square. But Saint John obtained the hand afterwards, and invoked the Blessed Virgin in a prayer which has been preserved; he prayed to be able to continue to write the praises of Her Son and Herself.
The next morning when he awoke, he found his hand joined again to the arm, leaving no trace of pain, but only a fine red line like a bracelet, marking the site of the miracle.
The Saint was reinstated afterwards to the favor of the local prince, but he believed that heaven had made it clear he was destined to serve the Church by his writings.
He therefore distributed his property and retired soon thereafter to the monastery of Saint Sabas near Jerusalem, where he spent most of his remaining years in apologetic writings and prayer.
Occasionally he left to console the Christians of Syria and Palestine and strengthen them, even going to Constantinople in the hope of obtaining martyrdom there.
However, he was able to return to his monastery.
There he died in peace at the age of 104, and was buried near the door of the monastery church, in the year 780.
(SOURCE: Les Petits Bollandistes: Vies des Saints, by Msgr. Paul Guérin (Bloud et Barral: Paris, 1882), Vol. 5;The Catholic Encyclopedia, edited by C. G. Herbermann with numerous collaborators (Appleton Company: New York, 1908).)