This comparative historiographical project examines the roles of dream narratives in Persian and Arabic language local histories. Specifically, this paper considers dreams as tools of legitimation and prophecy in Arabic and Persian language city, regional, and conquest histories from the 10th-13th centuries. I argue that through dream narratives, which often involve the Prophet or other pious exemplars, authors posit a powerful form of non-biological lineage and heirship to the Prophet. I integrate dream narratives into the broader mosaic framework of literatures – including the rich corpus of literature about dreams in the Qur’an, hadith, tafsir, and oneirocritical manuals – that informs but is not always explicit in these histories. My goal is to uncover the contexts and functions of dream narratives and expand the use of local histories by incorporating their treatments of dreams into a broader framework that encompasses the discourse of authority, piety, and literary self-representation. My sources are Persian and Arabic language city and regional histories, including but not limited to T?r?kh-i Bukhara by Narshakhi (d. 959), T?r?kh-i Tabaristan by Ibn Isfandiyar (d. after 613/1217), and T?r?kh Iftit?ah al-Andalus by Ibn al-Qutiyah (d. 977). Much of the previous literature on these histories has focused on administrative, political, and social history, and dream narratives have been overlooked. These dream narratives assert a supra-biological pedigree and form of legitimation for individuals, actions, regions, and cities through dream narratives involving the Prophet, Companions, abdal, Khidr, and pious characters. Claims of heirship or association with the Prophet through dreams transcends time and space, and dream episodes are one amongst multiple literary strategies employed in local histories to forge links with foundational moments and characters in Islamic history. In this paper I also consider how and when dreams gained traction in local historical writing as tools of legitimation and prophecy. I address whether certain elements – such as dreams and visions of Khidr and Muhammad – gained currency in historical writing through the popularization of Sufism. I use a functionally skeptical methodology that understands dream narratives as literary artifacts of early Islamic social life and cultural production. I approach the historiography of this period in a way that is attuned to structural differences in the production of historical writing, including issues of patronage, translation, and commissioned works. I also identify patterns common to historical writing of the same or relate genres written in disparate regions along the geographic peripheries of the Islamic empire.