Al-Kindi

Al-Kindi was called the philosopher of the Arabs, the first to take up Greek philosophy in Arabic, working in ninth-century Baghdad under the caliphs who sponsored the translation of Aristotle, Plotinus and the mathematicians. He wrote on everything, some two hundred and sixty works, of which a fraction survive, on optics, music, cryptography, medicine and the intellect. On the Intellect, a short treatise distinguishing four senses of the word, set the terms for al-Farabi, Avicenna and the Latin scholastics, who read it in translation. He fell from favour and was beaten, and his library was confiscated.