(767-820), who codified the basic principles of Islamic jurisprudence in his book ar-Risalah. The book details the four roots of law (Qur'an, sunnah, ijma, and qiyas) while specifying that the primary Islamic texts (the Qur'an and the hadith) be understood according to objective rules of interpretation derived from scientific study of the Arabic language.

Secondary sources of law were developed and refined over