This article contributes to the ongoing debate on the causes of the great divergence by comparing the use of expensive labour‐saving capital goods—water‐mills, windmills, and cranes—in medieval western Europe and the Middle East. Using novel ways of measuring, we find that whereas the use of these goods increased in Europe, in the Middle East their prevalence decreased, or they were not used at all. We investigate several possible explanations and reject most of them, including religion, geography, technological knowledge, and disparities in wages and cost of capital. Our analysis shows that differences in lordship systems and the security of property rights best explain the patterns found.