In this article, I develop and test a new methodology of unearthing early Shii ḥadı̄th sources that served as the basis for the later collections of the fourth/tenth century. This method, besides answering the question of historicity, enables us to understand the dissemination of texts across times and regions. As a case-study, I examine what is alleged to have been the first Shii legal ḥadı̄th collection, a work attributed to ʿUbaydullāh b. ʿAlī al-Ḥalabī (d. c. 148/765). By comparing the reports transmitted on the authority of al-Ḥalabī in the Twelver ḥadı̄th compendium originating in Qum, al-Kulaynī's al-Kāfī, and an Ismaili legal ḥadı̄th composition, al-Qāḍī al-Nuʿmān's al-Īḍāḥ, composed in Qayrawān, I demonstrate that both works trace their material to an earlier Kūfan source of the second/eighth century, with each work drawing on the same material independently. A cross-regional textual analysis of later ḥadı̄th compendia, in this case composed by contemporaneous scholars, residing in different regions, affiliated to dissimilar religious persuasions, reveals the transmission of identical material; this finding contributes to our understanding of both geographical transmission of early sources and compositional arrangements of the later ḥadı̄th compendia.