John Philoponus (Greek: ; ; c. 490 – c. 570), also known as John the Grammarian or John of Alexandria, was a Byzantine Greek philologist, Aristotelian commentator, Christian theologian and an author of a considerable number of philosophical treatises and theological works. He was born in Alexandria. A rigorous, sometimes polemical writer and an original thinker who was controversial in his own time, John Philoponus broke from the Aristotelian–Neoplatonic tradition, questioning methodology and eventually leading to empiricism in the natural sciences. He was one of the first to propose a "theory of impetus" similar to the modern concept of inertia over Aristotelian dynamics. Later in life Philoponus turned to Christian apologetics, arguing against the eternity of the world, a theory which formed the basis of pagan attacks on the Christian doctrine of Creation. He also wrote on Christology and was posthumously condemned as a heretic by the Church in 680–81 because of what was perceived as a tritheistic interpretation of the Trinity. His by-name translates as "lover of toil", i.e. "diligent," referring to a miaphysite confraternity in Alexandria, the philoponoi, who were active in debating pagan (i.e. Neoplatonic) philosophers. His posthumous condemnation limited the spread of his writing, but copies of his work, The contra Aristotelem, resurfaced in medieval Europe, through translations from Arabic of his quotes included in the work of Simplicius of Cilicia, which was debated in length by Muslim philosophers such as al-Farabi, Avicenna, al-Ghazali and later Averroes, influencing Bonaventure and Buridan in Christian Western Europe, but also Rabbanite Jews such as Maimonides and Gersonides, who also used his arguments against their Karaite rivals. His work was largely debated in the Arabic scholarly tradition, where he is known as (i.e. "John the Grammarian"), and his views against Aristotelian physics were defended by philosophers at the court of Fatimid Imam Al-Hakim bi-Amr Allah, particularly Hamid al-Din al-Kirmani, who debated Avicenna on the topic, and Hamza ibn Ali. His critique of Aristotle in the Physics commentary was a major influence on Giovanni Pico della Mirandola and Galileo Galilei, who cited Philoponus substantially in his works. Life Although Philoponus' originating from a Christian family is possible, nothing is known of his early life. Philoponus studied at the school of Alexandria and began publishing from about 510. He was a pupil and sometime amanuensis to the Neoplatonic philosopher Ammonius Hermiae, who had studied at Athens under Proclus. Philoponus' early writings are