This paper will address the question of the expansion (cast her as the "rediscovery") of the category of "Sahaba" and of the concept of ta‘dil in medieval biographical dictionaries. The broader context for this inquiry is specifically anti-Shi'i, examining the expansion of ta‘dil al-Sahaba and Sunni understandings of protection from sinfulness and error, under the broad category of ‘isma. Revivalist interpretations of the Sahaba and of ta‘dil ought to be seen as rejoinders to the development of Imami Shi‘i concepts also found under the broad category of ‘isma. I will therefore suggest a more contextualized corrective to some current understandings of ta‘dil al-Sahaba as a mere hadith mechanism invented by early traditionists, and address the broader question of how modern scholarship on Islamic intellectual history has often been dominated, occasionally ahistorically, by hadith studies Underlying the impulse (in medieval formulations of "orthodoxy") to revive older concepts and redeploy them to new ends is a recognition of the legitimizing power of historical continuity. The paper will interrogate that historicizing impulse, arguing against continuity with a static version of the past as the main mechanism of legitimation in formulations of “orthodoxy” or right belief. In the post-formative period, received versions of the past may not have been as subject to reconstruction as they had been previously, but they were freshly open to being endowed with new symbolic meaning. This is, in one way, the very essence of “revival.” To put it differently, the Sunni doctrine of ta‘dil al-Sahaba and the subsequent expansion of the number of Companions in biographical dictionaries to many thousands from the 4th/10th to the 9th/15th centuries is more than the result of a technical maneuver by early hadith scholars, and is part of broader discourses at stake during the Sunni resurgence.