3rd quarter of the 7th c. – mid-8th c.

John of Damascus – the last of the Greek Fathers

John Mansur was born in Damascus under Muslim rule and, like his father, served for a time at the caliph's court. He then became a monk and priest at the Lavra of St. Sabbas near Jerusalem. His principal work, the "Fount of Knowledge" (the Dialectic, the Book of Heresies, and An Exact Exposition of the Orthodox Faith), brought together philosophical premises, the history of heresies (including Islam among them), and Orthodox dogmatics.

John became the first great apologist for icons and in his "Three Treatises in Defense of the Holy Icons" spoke out against iconoclasm. His writings were anathematized by the iconoclast council of 754, and the Seventh Ecumenical Council of 787 vindicated them. An early Latin translation of the "Fount of Knowledge" later influenced Western scholasticism.