I study the usage of the twelve-month cyclical Turkī calendar in Safavid court chronicles under the reigns of Tahmasp I (1524-1576 A.D.) and Abbas I (1588-1629). I first track the introduction and establishment of this dating system under the Ilkhanate (1256-1335). I then examine the sixteenth-century adaptation and mobilization of the Turkī calendar in Safavid historiography. I offer a comparative study between the usage of Turkī and Hiǧrī chronologies by the Safavid historians to demonstrate how the exclusive adoption of Turkī calendar with respect to the Ilkhanid and Timurid dynasties generated a distinctive and parallel ‘Turkī timeline’ in contrast to the more inclusive ‘Hiǧrī timeline’. In doing so, the Safavid chroniclers accentuated the historical continuities between the Safavid shahs and their Chinggisid and Timurid predecessors. I explore this time-keeping device to ponder how the Safavids claimed Chinggisid heritage for themselves as well as over other post-Mongol polities such as in Bukhara and in Khwarazm. Reactivating the Turkī calendar, I argue, served a double purpose. First, this allowed the Safavids to assert chronological continuity, which was instrumental in politically legitimizing them as the latest in a succession of post-Mongol dynasties ruling Iran. I argue that claiming Mongol continuity was a critical mechanism of advancing historical legacy for the newly established Safavid sovereignty. Calendars served the dual purpose of presenting a chronologically contiguous Safavid past with the Mongols as well as inaugurating a coherent map for the Safavid future. Second, using the Turkī calendar in annalistic court histories provided the Safavid Shahs with a distinctive Chinggisid and Timurid trait, establishing the Safavids within an aggressively competitive post-Mongol world. This symbolic claim of Mongol heritage also contributed to the broader imperial imagery of the Safavid Shahs in a similar way as, for instance, their affirmation of descent from the Seventh Imam Mūsà al-Kāżim. Safavid historiography has typically presented the Shahs as distinctive figures, presenting them as ‘restorers’ of ‘Persian’ monarchy after centuries of Turco-Mongol rule. My paper contests this claim by showing how some of the fundamental practices of Safavid sovereignty such as that of time-keeping was drawn from their desire to highlight their Mongol heritage. Finally, studying this autochthonous time-keeping device helps to challenge the universality accorded to the Hiǧrī calendar as by-default chronological standard for Safavid historiography. Focusing on this non-linear cyclical timeline might allow us to examine the way Safavids conceptualized time as a component of early modern sovereign power.