Malik Ṣadr al-Dīn Tabrīzī (d. 668/1269–70) was one of the most important individuals to the establishment of Mongol rule in Iran. His biography illustrates like few others not only themes of mobility and cross-cultural contacts across Eurasia but also the importance of local elites to the formation of the empire of Chinggis Khan and his descendants. Malik Ṣadr al-Dīn belonged to a notable family of Tabriz and served as governor of his native city soon after the definitive Mongol conquest of 628/1231. He traveled to Mongolia in 649/1251 and was put in charge of implementing a revised imperial taxation system in northwestern Iran by Great Khan Möngke. Then Malik Ṣadr al-Dīn remained a key player in the financial administration of the emerging Ilkhanate as Möngke’s brother Hülegü asserted his claims to the northwestern core area of Mongol Iran against his enemies from the house of Jochi. Despite connections of Malik Ṣadr al-Dīn’s family to the Jochids, he continued as governor of Tabriz where he also acted as a patron of Persian literature until his death. So far Malik Ṣadr al-Dīn has gone almost unnoticed in historical scholarship.