The 13 th century witnessed a substantial increase in inequality in the distribution of peasant landholdings relative to the distribution of the late 11 th century. Innovations in property rights over land in 12 th century England induced peasants to include the trading of small parcels of land as part of their risk coping strategy. We argue that these events are related. Recent theoretical work in development economics has explored the relationship between inequality and asset markets. When agents are able to trade productive assets to manage risk, the resulting dynamics may generate increasing inequality over time. We employ a simulation strategy to analyze the impact of land markets in generating inequality in 13 th century landholdings. We find that the dominant factor contributing to the unequal distribution of land was the interaction between emerging land markets and population growth driven by high fertility rates in households with large landholdings.Keywords: economic history, land market, Hundred Rolls, Domesday, inequality, risk, poverty, asset markets, simulation analysis, economic development JEL Classifications: N23, N53, O15, J11 ⇤ This paper has benefited from comments and suggestions from audiences at an ASSA Cliometric session in Chicago, the CNEH Conference in Montreal, and Oxford University. We are indebted to Bruce Campbell, Jeff Dunbar, Rui Esteves, Erin Haswell, and Alex Karaivanov for comments and encouragement. Rick Bekar helped with coding the simulations. Tamma Carleton provided valuable research assistance. All are absolved of responsibility.