John Scotus Eriugena, also known as Johannes Scotus Erigena, John the Scot or John the Irish-born, was an Irish Neoplatonist philosopher, theologian and poet of the Early Middle Ages. Bertrand Russell dubbed him "the most astonishing person of the ninth century". The Stanford Encyclopedia of Philosophy states that he "is the most significant Irish intellectual of the early monastic period. He is generally recognized to be both the outstanding philosopher of the Carolingian era and of the whole period of Latin philosophy stretching from Boethius to Anselm". c. 800 – 877; died at about 77. Alive at the same time as Muḥammad ibn Musa al-Khwarizmi, Alfred the Great, Jabir ibn Hayyan, Al-Shafi'i, and Ādi Shankara. Wiki link