Sectarianism emerged early in Islamic history. The major split, between Sunni and Shi‘a leadership, centered on questions of authority and political legitimacy. By the 2nd century of the Islamic era, this split had affected the production and trajectories of traditional literature, including hadith (sayings by and about Muhammad). As each camp devised different ways to understand the past, Sunnism became more than a "side" in the factionalization that resulted from the controversial caliphate of Ali.
The designation "Sunni" contains theological and legal implications. In the first centuries of Islamic life, from the mid-7th to the 10th century or so, a system of Islamic law that encapsulated what would become a typically Sunni approach to the interpreting the Quran (scripture) and hadith would develop slowly and organically, alongside other branches of study like theology, philosophy, grammar, and other disciplines.
The Sunni schools of law, four of which have survived in significant numbers and continue to exist today, incorporate their own historical vision and interpretive methodologies. Often, the term shariah is used as a synonym for Islamic law, but this is a misnomer. Shariah is a term for a way of life, a legal system within a belief system. A more accurate synonym for law or jurisprudence in Arabic is fiqh.
Islamic law, as an organized scholarly field, developed rather early relative to other genres of Islamic scholarship. It is a sophisticated and comprehensive legal system, which has occasionally led modern scholars to characterize Islam as an extremely litigious religion. However, in a manner more analogous to Jewish law, Islamic law is one component of a broader system of belief and practice. Based on the hadith, it was necessarily a system that incorporated a sense of history, of tradition, and of a communal identity. The formation of Islamic law, then, is central to the historical development of the Muslim community.
The Islamic World expansion, 622-750
The term shariah, literally "a way," occurs in both the Quran and the hadith. In spite of such austere origins, interpreters and exegetes have never been shy about exploring legal definitions and applications in a variety of ways, which led to their creation of systems and rules of interpretation. In other words, despite its sacred meaning for Muslims, religious law was not to be handled with kid gloves. For the first three centuries of Islamic history, legal scholars interpreted shariah for an adapting and growing Empire.
No system of thought or cultural development begins ex nihilo. In terms of Sunni law, pre-existing norms, from the Arabian Peninsula as well as from the well-established Sasanian (Persian) Empire, affected patterns of early Islamic thought. For example, the law of retaliation for bodily crimes against specific people already existed in the Arabian Peninsula before the dawn of Islam. It was incorporated, with some modification, into an Islamic legal principle called qisas. While the Quran contains injunctions regarding elements of Islamic conduct, and despite the fact that many of its verses regarding inheritance or divorce are quite litigious, the scripture does not contain an actual law code. The hadith, obviously important for rounding out interpretation of the scripture, were vast and numerous and already a subject of their own study. Combining interpretations of these sources required theoretical structures to accommodate the needs of the changing Islamic empire.
Umayyad caliphate at its greatest extent (750 CE): PublicDomainMoreover, the empire was indeed growing. Over the course of just under a hundred years, the Umayyad dynasty presided over the expansion of Islam into India, North Africa, and Spain. To legislate matters of everyday life in these diverse areas, judges called qadis presided over the affairs of the Muslim populations. In the following century, the Abbasid dynasty ruled from its own capital, Baghdad, a period that began the age commonly referred to as the "Golden Age" of Islamic thought. Impacted enormously by sophisticated Persian court culture, the Abbasids had their own views about the centralization of government, while provincial qadis continued to preside over civil law
Over time it became inevitable, however, that local concerns and customs would engender different interpretations of law. Different legal systems began to develop in several regions. There is no official clerical class, doctrinal council, or sole spiritual authority in Islamic society. The formalization of Islamic law was therefore organic and multi-faceted. Four schools of Sunni law exist today. Developed through generations of students and scholars, these four "schools of law," or madhahib in Arabic, are named for the teachers whose approach to hadith and religious practice was later elaborated on. It is important to remember that these schools are not distinguished from one another along doctrinal lines; they differ, rather, in terms of the execution of certain ritual and practical aspects of Islam and in their approaches to the interpretation of sources. Adherents of each Sunni school all regard one another as valid. The four remaining schools of Sunni law and their eponymous founders are:
The Hanafi School, named after Abu Hanifa (d. 767)
The Maliki School, named after Malik ibn Anas (d. 796)
The Shafi‘i School, named after Muhammad ibn Idris al-Shafi‘i (d. 820)
The Hanbali School, named after Ahmad bin Hanbal (d. 855)
Al-Shafi‘i (the Shafi'i School) in particular had an enormous impact on the formalization of Sunni approaches to Islamic law, arguing for the primacy of the Quran, followed by the hadith. If those two sources failed to produce adequate guidance on a matter, a qadi was to seek the guidance of the consensus, called ijma‘, of other legal scholars. Only as a final recourse should a qadi rely upon his own judgment in finding some analogous precedent. Originally, this inspired some controversy, as other jurists were more comfortable resorting to their own judgment, or ra'y, in times of necessity. Camps termed the ahl al-hadith ("proponents of tradition") and the ahl al-ra'y ("proponents of reason") argued over the validity of their differing approaches. In spite of these controversies, Al-Shafi‘i had a major and lasting impact on Sunni Islam.