Al-ʿAbbās ibn Saʿid al-Jawharī (; ), known as Al-Jawhari, was a geometer who worked at the House of Wisdom in Baghdad and for in a short time in Damascus, where he made astronomical observations. Born (and probably dying) in Baghdad, he was probably of Iranian origin. His most important work was his commentary on Euclid's Elements, which contained nearly 50 additional propositions and an attempted mathematical proof of the parallel postulate. Described as having superb knowledge of Greek, which was unusual for a Muslim scholar), Al-Jawhari is credited with a translation into Arabic of the Indian polymath Shanaq al-Hindi's Book of Poisons. References Sources Further reading (PDF version) 800s births 860 deaths People from Baghdad 9th-century Iranian mathematicians 9th-century mathematicians 9th-century people from the Abbasid Caliphate Mathematicians from the Abbasid Caliphate Astronomers from the Abbasid Caliphate Astronomers of the medieval Islamic world Middle Persian–Arabic translators 9th-century Arabic writers