Sibawayh (148-180 AH / 765-796 AD), known by his allegiance as Amr ibn Uthman ibn Qanbar al-Harithi, was known as Abu Bishr and was nicknamed Sibawayh. He was the imam of grammarians and the first to simplify the science of grammar. He studied grammar and literature under al-Khalil ibn Ahmad al-Farahidi, Yunus ibn Habib, Abu al-Khattab al-Akhfash, and Isa ibn Umar. He arrived in Baghdad and debated al-Kisa’i, defeating him in a case known as the Zanbariyya Question. Al-Kisa’i prevailed over Sibawayh, but Sibawayh did not remain in Baghdad after this debate and returned to Persia, never to Basra. Among his works is Sibawayh’s book on grammar.