John the Deacon was a Monophysite Egyptian chronicler whose Life of the Patriarch Michael, finished c.768–70, is the most important source for Christian Nubia in the first half of the eighth century.
[1] His book, written in Coptic, was later translated into Arabic and incorporated as the second part of the History of the Patriarchs of Alexandria.
[2] John was a spiritual disciple of Bishop Moses of Awsim, one of the most revered Coptic churchmen of his age.
For instance, he records a Nubian invasion of Egypt that reached as far as Fustat in 745, after the Egyptians refused to release Michael, Patriarch of Alexandria.
[1] This event appears to be a conflation of a real invasion of Upper Egypt and the imprisonment and liberation of the patriarch, made to coincide with a known period of Coptic uprisings and consequent persecution at the instigation of the Caliph Marwan II.