Modern scholarship has hastily dismissed the Abbasid Caliphs who reigned under the protection of the Mamluk Sultans of Egypt and Syria (1261-1517) as political sham. To be sure, securing political legitimacy for a class of slave rulers was a main concern behind the transplanting of an Abbasid scion to Cairo, at least in the beginning. However, there is good reason to believe that among the people at large, the ‘ulama’, and even among the Mamluk amirs themselves, there were other considerations that made the Caliphs important and even indispensible presences on the political stage. This importance often transcended their actual political authority, meager as it was, in ways that are starting to become evident. One example of this importance centers about the Abbasid Caliphs' relationship with the shrine of Sayyida Nafisa (d. 824) in Cairo. This was a well-established destination for pilgrims who came to venerate since the Fatimid era. In 1341, the Mamluk Sultan awarded control of the shrine’s administration to the Abbasid family, where it remained until the Ottoman invasion of 1516-17. This action accentuated Caliphal importance and reconnected the Abbasids with the civilian public after years of intermittent confinement in the Citadel. Connection with the Saint identified the Abbasid line in the public consciousness with the other extant branch of the Prophet's family: the Alids. Becoming guardians of the shrine’s baraka, a wellspring of popular culture and piety in Cairo, provided a new religious authority for the Abbasids and bolstered reverence for the Caliphs among visitors to the shrine. This paper will execute a much needed reexamination of the religious authority of the Abbasid Caliphate in Cairo, focusing on the shrine of Sayidda Nafisa. It will also examine wider post-Mongol conceptions of Caliphal authority. The sources for study will include Mamluk period chronicles, topographic manuals of the khitat genre and biographical dictionaries which will be cross-examined to shed light on the Cairo Caliphs and their unique relationship with the shrine and devotees of a 9th century Muslim saint, the better to illustrate notions of evolving political authority in the Islamic Middle Period.