This article examines material that points to the existence in pre-classical Imamism of views on the subject of the imam's knowledge and the related question of sources (usūl) of Imami law, which are at variance with the views attested in the classical sources. The evidence shows that al-Fadl b. Shādhān refuted the possibility of divine inspiration for the imam and maintained that the imam's religious knowledge was based entirely on transmission from the Prophet and restricted to the Quran (a complete and perfect source) and its interpretation. It also provides a strong indication that the doctrine of tahrif and the idea of a ‘complete’ ‘Alid codex had originally served to support the claim that the imams’ teachings were based entirely on the Quran. Other evidence examined here suggests that al-Fadl's views are likely to have been representative of the ‘orthodox’ (viz. the legalist and non-ghuluww) position in early Imamism.