Abd al-Masih ibn Ishaq al-Kindi was a Christian Arab scholar and courtier at the court of the Abbasid Caliph Al-Mamun in Baghdad, writing in the early ninth century. Of noble descent from the Beni Kinda tribe of Arabia — one of the great pre-Islamic clans — he belonged to a branch that had retained its Christian faith through the rise of Islam. His name, Abd al-Masih ("Servant of the Messiah"), signals that Christian identity openly.
Almost nothing is known of his life beyond what can be inferred from his one surviving work. He was a Nestorian Christian, learned in philosophy, Arabic rhetoric, and the scriptures of multiple traditions, and was held in sufficient standing at the Caliph's court that his extended written defence of Christianity against Islam circulated without apparent official suppression — a fact that says as much about Al-Mamun's unusual intellectual tolerance as about al-Kindi's position.
He should not be confused with his near-contemporary Abu Yusuf ibn Ishaq al-Kindi, the celebrated Muslim philosopher known as "the Philosopher of Islam," who also flourished at Al-Mamun's court and who in fact wrote against the doctrine of the Trinity.