Macuch, Maria. 2017. Descent and inheritance in Zoroastrian and Shiʿite law: A preliminary study. Der Islam 94(2). 322–335.
The Twelver Shiʿite law of inheritance constitutes one of the most distinctive features of the legal system in comparison with Sunni law. Although there are major and even irreconcilable divergences between the Sunnite law of succession according to all four legal schools on the one hand and Twelver Shiʿite law on the other, no convincing explanations for this striking development within Islamic law itself, leading to two fundamentally distinct systems, have hitherto been put forward. The aim of this preliminary study is to call attention to several remarkable correspondences between the complex Iranian (Zoroastrian) law of succession, conceived to support the specific needs of aristocratic descent groups in the Sasanian period, and Twelver Shiʿite regulations, reflecting a very similar underlying concept of family ties and descent groups as a whole. The question is, whether these congruencies are purely coincidental or based on age-old social and traditional norms, which continued to be practised in the regions of the former Sasanian empire after the Islamic conquest. As Sasanian norms remained operative in customary law (now documented by Pahlavi legal documents from 8th century Tabarestān) during the formative period of Islamic law and the Sunnite regulations, being based to a large extent on pre-Islamic tribal law in Arabia, contrast sharply with the Shiʿite concept, it would be consistent to assume that certain precepts in the pre-Islamic Iranian system had an important impact on the development of the Twelver Shiʿite law of inheritance.