Grammarians of Basra
The first Grammarians of Baṣra lived during the seventh century in Al-Baṣrah. The town, which developed out of a military encampment, with buildings being constructed circa 638 AD, became the intellectual hub for grammarians, linguists, poets, philologists, genealogists, traditionists, zoologists, meteorologists, and above all exegetes of Qur’ānic tafsir and Ḥadīth, from across the Islamic world. These scholars of the Islamic Golden Age were pioneers of literary style and the sciences of Arabic grammar in the broadest sense. Their teachings and writings became the canon of the Arabic language. Shortly after the Basran school's foundation, a  rival school was established at al-Kūfah circa 670, by philologists known as the Grammarians of Kūfah. Intense competition arose between the two schools, and public disputations and adjudications between scholars were often held at the behest of the caliphal courts. Later many scholars moved to the court at Baghdad, where a third school developed which blended many ideological and theological characteristics of the two. Many language scholars carried great influence and political power as court companions, tutors, etc., to the caliphs, and many were retained on substantial pensions. Ishāq al-Nadīm—the 10th century author of "Kitab al-Fihrist"—provides  a trove of biographical accounts of the leading figures of the two schools and would seem to be the earliest source. However greatly augmented biographical detail can be found in a number of later encyclopedic dictionaries, by authors such as Ibn Khallikan, Suyuti, and others. Basra, Kufa, and subsequently Baghdad, represent the main schools of innovation and development of Arabic grammar and punctuation, linguistics, philology, Quranic exegesis and recital, Hadith, poetry and literature.