This article examines the role of pre-Islamic Iran’s scientific and institutional heritage in the flourishing of mathematics in Islamic civilization from the perspective of the history of science. It argues that the prominent role of the Iranian cultural sphere in the development of Islamic mathematics cannot be explained solely by the transmission of earlier scientific traditions or by individual achievements. Rather, it should be understood through the interaction between inherited scientific and institutional capacities, the new intellectual and practical demands of Islamic society, and the formation of scholarly networks in the Islamic period.

Before the advent of Islam, Sasanian Iran had developed traditions in astronomy, calendrical studies, administrative calculation, and intellectual exchange with Greek, Indian, and Syriac scientific cultures. These capacities did not disappear after the emergence of Islam; instead, they were transformed and integrated into a new historical context. At the same time, religious and social requirements of Islam, including the determination of prayer times, the calculation of the qibla direction, calendar regulation, and legal computations, created new demands for mathematical and astronomical methods.

By examining historical evidence from pre-Islamic Iran and the contributions of scholars such as al-Khwārizmī, al-Bīrūnī, ʿUmar Khayyām, and Naṣīr al-Dīn al-Ṭūsī, this article argues that the flourishing of mathematics in the Iranian cultural sphere resulted from the activation of pre-existing capacities in response to new needs and within the institutional framework of Islamic civilization. The development of Islamic mathematics is therefore best understood as a multifactorial process shaped by historical continuity, cultural interaction, and scholarly creativity.