Shirazi's "Tabaqat", which Hallaq labels "an important early biographical work dedicated to jurists", covered 84 "towering figures" of Islamic jurisprudence; to which Kufa provided 20. It was therefore a center surpassed only by Medina (22), although Basra came close (17). Kufans could claim that the more prominent of Muhammad's Companions had called that city home: not only Ibn Abu Waqqas, Abu Musa, and Ali; but also Abd Allah ibn Mas'ud, Salman the Persian, Ammar ibn Yasir, and Huzayfa ibn Yaman. Among its jurists prior to Abu Hanifa, Hallaq singles out Sa'id ibn Jubayr, Ibrahim al-Nakha‘i, and Hammad ibn Abi Sulayman; and considers Amir al-Sha‘bi a pioneer in the science of judicial precedent.