The idea of the ghayba has been a centerpiece of Shi‘i Islam throughout its storied history. Although there has emerged since the 1970s a considerable corpus of scholarship on the ghayba-idea in Twelver Shi‘ism, considerably less scholarship has been devoted to studying its pre-Twelver instantiations. My paper aims to rectify this current historical bias by shining direct light on the ghayba-idea’s earliest instantiations in the late-Umayyad and early-Abbasid period. Such a shift in focus, I argue, produces several exceptional insights. Firstly, there are insights into the emergence of the ghayba-idea itself: whence does it enter Shi‘ism and how is it able to take hold of Shi‘ite belief thereafter? The first Shi‘ites to espouse belief in a ghayba of their imam are the Kaysaniyya, whose poets preserve for us the earliest testimony to the belief that their Mahdi – ‘Ali’s son Ibn al-Hanafiyya (d. ca.700) – had not died but was rather hidden in the mountains outside Medina where he awaited the time of his triumphant return. I argue that the belief’s roots must lie in the currents of late antique messianism that flourished during the Perso-Byzantine War of 602-28, the Islamic conquests, and the Abbasid revolution—currents that the early Shi?ites proved adept at navigating throughout the seventh and eighth centuries. The second enigma of the ghayba-idea that arises – and, in my view, the least noticed – is its rapid expansion and dissemination in the eighth century CE. After the emergence of the ghayba-idea among the Kaysaniyya in the early eighth century, this belief does not become merely an idiosyncratic doctrine of disappointed millenarians—it spreads like wildfire across of the eastern lands of the Islamic caliphate. For period spanning 700-800 CE, Muslim scholars record at least nine persons who reputedly entered ghayba; at least five of these ghaybas are espoused by non-Muslims (e.g., the followers of the Jewish rebel Abu ‘Isa al-Isfahani and the Abu-Muslimiyya). Furthermore, most of these persons said to have entered ghayba tend to cluster around the Hashimite movement that gave rise to the Abbasid revolution in 750. Is this apparent dissemination of the ghayba-idea merely the artificial byproduct of Muslim author’s using heresiological tropes?—Or, is there something about the alchemic mingling of messianic ideas enabled by the Hashimite movement in Khurasan that, when passed through the alembic of the Abbasid revolution, produced this incredible spread of the Shi‘ite ghayba-idea?