Mortgage markets in developing economies are often confined to private networks. Inadequate registration of property rights has been blamed for this, but it is questionable whether registration provides a simple and complete solution. This paper addresses this issue by analysing the Low Countries, where registration was organised well, and England, where registration was organised poorly, between 1300 and 1800. These historical cases show that registration was important but did neither provide a simple nor a complete solution for the emergence of broad mortgage markets. Successful historical markets took considerable time to appear and also addressed mortgage law and financial intermediation.