How did the Mongols finance imperial expansion and administer the vast territories under their control? Although the Mongol Empire was built on horseback, it was sustained through sophisticated fiscal arrangements and financial innovations. This book examines the financial institutions of the Mongols through new interpretations of fiscal administration, business partnerships, tax farming, and state intervention with the focus on the Middle East. Under Mongol rule, long-distance trade reached an unprecedented scale, linking China, the Middle East, and Europe through networks that relied in part on the flexible arrangements of ortoq partnerships designed to meet the economic needs of the time. Drawing on a wide range of historical sources, this study challenges long-standing assumptions about the economic consequences of the Mongol conquests and offers a new understanding of how financial institutions helped build, sustain, and transform one of history's largest empires, whose economic legacy continued to shape Asian and European economies for centuries.