Timekeepers and the Problem of Religious Authority in 16th-Century Ottoman Istanbul

By the thirteenth century, Islamic religious practices surrounding the five daily prayers had uniquely integrated systematic and technically sophisticated scientific procedures into the routine determination of ritual obligations. Muvakkits—official timekeepers charged with calculating the daily fluctuating prayer times—relied on dense technical knowledge preserved in tables and handbooks and affirmed through observation with instruments. Yet this scientific expertise, despite being developed expressly in the service of religious observance, was not always publicly recognized as authoritative.

This instability is evident in the writings of Mustafa ibn Ali al-Muvakkit (d. 1571), among the most prolific astronomical experts of sixteenth-century Ottoman Istanbul. In his discussion concerning the proper moment of sunset—crucial for both the evening prayer and the breaking of the fast during Ramadan—Mustafa emphasizes that sunset, as defined by astronomical calculation, does not require the complete visual disappearance of daylight. He observes, however, that many members of the public rejected this definition, preferring to anchor religious time in visible darkness rather than in computation. Mustafa further complains that timekeepers were accused of ignorance, and that even learned figures sometimes sided with popular opinion against technically grounded determinations.

Rather than reinforcing a familiar narrative of tension between science and religion, this episode reveals how tensions between scientific expertise and popular practice could unfold within a religious framework that already depended on calculation. By examining disputes over calculating prayer times, this paper shows how Ottoman religious timekeeping became a contested arena in which mathematical abstraction and claims to moral authority intersected, rendering sacred time subject to negotiation rather than unilaterally enforced.