|The succession of Shi`ite leaders comprised an unbroken line of the imams of the Ahl al-Bayt (PBUT), beginning with Imam `Ali (PBUH) in the 1st century AH and continuing into the 2nd and 3rd centuries AH with the likes of imams al-Baqir and al-Sadiq (PBUT) who were recognized by various fiqhi schools as distinguished faqihs. It should be borne in mind that the emphasis placed by the imams on the various aspects of fiqhi thinking and education was in tune with the social conditions and cultural needs of the day and thus it appears likely that the codification of the Imami fiqh into a cohesive system was in fact simultaneous with the same development in other schools of Islamic fiqh, a fact that was brought about as a result of the efforts of Imam al-Sadiq (PBUH).
An analysis of Shi`ite fiqhi tendencies in the first centuries AH is made less than facile by two factors: major structural developments, and the paucity of clear evidence regarding its earlier history. At present, the only means of gaining knowledge of the various aspects of the fiqhi systems of the time of the imams (PBUT) is through reports contained in hadiths preserved in the surviving traditional and fiqhi compendia. In these reports, fiqhi rules and opinions are, in the main, attributed to the Infallible Imams (PBUT). None the less, in cases of divergence between two or more hadiths of the imams (PBUT) the selection of the transmitters, who themselves are prominent faqihs, may be used as a window to their own fiqhi views.
In the early decades of the 2nd century AH, a number of Shi`ite scholars among the companions of the imams (PBUT), such as Jabir b. Yazid Ja`fi and Aban b. Taghalb, were known as prominent jurists among the fiqhi circles in Iraq. However, the Shi`ite fiqh as an independent school of jurisprudence only came into prominence during the days of the companions of Imam al-Sadiq (PBUH). Based on the positions taken in connection to the use of various fiqhi methods of reasoning, it may be broadly concluded that in the 2nd century AH there existed a number of distinct jurisprudential schools which made use of analytical techniques in addition to traditional sources. The first group comprised theologians whose leaders during two consecutive generations included such eminent personalities as Hisham b. Hakam and Yunus b. `Abd al-Rahman. The second group were represented by Hisham b. Salim, Safwan b. Yahya and Ahmad b. Muhammad b. Abi Nasr Baznati. The third school was dominated by the faqihs of the Al-i Yasin family, headed by Zararah b. A`yan and `Abd Allah b. Bukayr. There also were smaller circles led by the likes of Muhammad b. Muslim Thaghafi and Abu Basir Asadi. These groups, which may be categorized under the general title of the Partisans of Ijtihad, continued to flourish into the middle part of the 3rd century AH. A counter-movement was also forming which was distinguished by its vehement opposition to any attempt at personal reasoning and ijtihad beyond what was asserted in religious texts, one whose traces are found throughout the works of early Shi`ite traditionists. Apart from exceptional cases, it should be noted that in the 3rd century AH this atmosphere of common ijtihad dominated the teachings of Imami traditionists and theologians. Alongside the predominant fiqhi schools, the remnants of other factions from the previous century continued in existence for some time. These included the followers of Hisham b. Hakam in the 3rd century AH who in spite of their close views to those of the dominant schools continued to enjoy a relative advantage. They were led by such thinkers as Fadl b. Shadhan.
Towards the close of the 3rd century AH, the rejection of ijtihad and its related issues occupied a special chapter in the works of Traditionalist faqihs. This trend was continued into the coming century by faqihs who were part of the movement to codify the Imami fiqh. In their works, the texts of hadiths were made available to the seekers of fatwas as “common rules”. The most eminent examples of these works include al-Kafi of Kulayni, al-Sharayi` of `Ali b. Babawayh and Man la Yahzaruh al-faqih of Muhammad b. Babawayh, none of which contained any considerable degree of their authors’ personal views. Here, Muhammad b. Babawayh went farther than denying legitimacy to ijtihad and lashed out against any attempts at fiqhi interpretation or deduction. Theologian faqihs were another group which opposed ijtihad. Prominent examples of their works include the refutations of Abu Sahl Nubakhti against the method of personal reasoning practiced by Ibn Rawandi and `Isa b. Aban, and those of Abu Nasr Suram Niyshaburi and a group of his fellow theologians against the use of qiyas (analogy) in fiqhi decisions. However, the best instances of Imami theologians’ opposition to the issue of ijtihad may be found in the works of Ibn Shadhan and Ibn Qubbah.
As regards the early Zaydite fiqh, mention must first be made of Zayd b. `Ali (PBUH), who based on a tradition contained in the Musnad of Zayd, believed that in case no rule was found in the Qur’an or the sunnah, recourse was to be made of the “consensus of the righteous”, and in case it still failed to produce a rule the next stage was to be that of ijtihad and analogical reasoning carried out by an imam or judge among the Muslim community. In the first half of the 3rd century AH, Ahmad b. `Isa b. Zayd and Qasim b. Ibrahim Rasi, two prominent Zaydite leaders, simultaneously established two schools of fiqh in Iraq and Hijaz. Soon, the principles of their fiqhi methods were compiled in a comparative work attributed to a Hasan b. Yahya in a work titled al-Jami` `ala madhhab al-Qasim wa Ahmad b. `Isa (A Compendium of the Religion of Qasim and Ahmad b. `Isa). The same comparative method of compilation was taken up by Muhammad b. Mansur Muradi (d. 290 AH) throughout his numerous works. Several factors contributed to the Zaydite fiqh, throughout its course of development, receiving extensive influence from its Hanafite counterpart. These included the existing intellectual affinities between the two schools, the Zaydites’ sympathy for Abu Hanifah because of his support of the Zaydite movement throughout its phase of uprisings, and the rising popularity of the Hanafite fiqh in all parts of Islamic world, owing to its progressive systematization.
The second half of the 3rd century AH witnessed the consolidation of two long-standing Zaydite schools of fiqh. The first school was founded by the Zaydite Imam Hadi ila ’l-Haqq, the descendent of Qasim Rasi, the founder of the Zaydite imamate of Yemen. Making use of Qasim’s fiqhi ideology and, more extensively, that of Abu Hanifah, Hadi succeeded in establishing a solid fiqhi system which came to be named after him as Hadawi fiqh. Apart from minor differences, Hadi’s fiqh is, in large part, in harmony with that of Abu Hanifah, so much so that according to Abu Talib Haruni, a Zaydite leader, in all cases where Hadi’s fatwa does not directly derive from a religious assertion (nass) it is in perfect concord with the opinion of Abu Hanifah on the same subject. As regards the characteristics of Qasimi-Hadawi fiqh, it may be noted that in spite of its considerable divergence from the Imami fiqh it does share a number similarities with the latter.
The second school of fiqh which developed simultaneously but along different lines from those of the Hadawi fiqh was founded by Nasir Atrush (d. 304 AH), the Zaydite leader of Tabaristan. His system, which came to be known as the Nasiri fiqh, was based on the Zaydite fiqh of Kufah and the transmitted Imami sources, with particular affinity to the Imami fiqh. Atrush’s fiqhi views were so similar to those of the Imamis that Sayyid Murtada throughout his al- Nasiriyyat engages in an analysis of his views and draws comparisons between them and those of the Imamis.