The author studies the silk trae in Eurasia between the seventh and twelfth centuries to explore how religious ideas and institutions affected economic behaviour. Long-distance silk trade had been established for centuries in ancient Eurasia, well before the state in Tang China and the Byzantine Empire set up state silk industries and clothing codes to regulate the trade and consumption of silk textiles. Silk textiles were invested with symbolic meaning and their use restricted to bureaucratic and religious hierarchies in both regions. Although this state monopoly never totally disappeared, silk textiles once again became commodities available in many parts of Eurasia after the tenth century. Religious concepts and institutions played a significant role in this process. Buddhism and Christianity facilitated the process of breaking state control over luxury goods, and Islamic regimes actually spread sericulture and silk-weaving technology over a vast area. This work will interest all those curious about medieval religion, culture and economic life.