This project explores how the Mongols’ transcontinental rule (thirteenth–fourteenth centuries) shaped the practices, institutions and exchange of astral sciences in China and West Asia. Under Mongol rule, both China and the Islamic world witnessed a vibrant and prolific era of astral sciences. Important innovations were made not only in astronomical ideas and practices, but also in astronomical institutions. Moreover, the Mongol courts cherished pluralism and brought various astronomical traditions into close contact with each other at an unprecedented scale. This project takes a comparative and holistic approach. It examines the instrumental role of the Mongols and their astral science experts in promoting science and mediating scientific exchange across Eurasia. This study sheds new light not only on the daily management of the Mongol Empire but also on the complex interplay between empire and knowledge.