This article examines the transformation of Western academic explanations of the origins of Shiʿism from Julius Wellhausen to Wilferd Madelung. It asks how the definition of “origins,” the unit of analysis, the hierarchy of sources, and the relationship between politics and religion changed across this historiographical trajectory. Employing analytical historiography and comparative source criticism, the study evaluates the works of Wellhausen, Ignaz Goldziher, Marshall Hodgson, W. Montgomery Watt, S. Husain M. Jafri, Heinz Halm, and Madelung according to five variables: the proposed starting point of Shiʿism, event-based versus processual temporality, the relationship between politics and religion, endogenous versus exogenous causation, and the use of sources. The findings show that Wellhausen, although locating Shiʿism within Arab society, principally interpreted it as an opposition party whose political defeats led to its religious development. Hodgson shifted the question from when Shiʿism originated to how it became sectarian; Watt added tribal, urban, and mawālī dimensions; and Jafri challenged the separation of a political phase from a religious one. By restoring the Qurʾan, the status of the Prophet’s family, kinship, material rights, and the plurality of Hāshimite claims to the center of analysis, Madelung criticized the conventional assumption that Abū Bakr’s succession was unproblematic. The article argues that this historiographical change was not a linear replacement of theories, but a relocation of explanatory emphasis from a “political party” to a multilayered process in which claims to authority, collective memory, religious leadership, and communal identity emerged at different times.