Al-Abbās ibn Said al-Jawharī

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 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.