A custumal is a medieval document, usually edited and composed over time, that stipulates the economic, political, and social customs of a manor or settlement. Real world historical archives define a custumal as “an early type of survey which consists of a list of the manor’s tenants with the customs under which each held his house and lands.”

Custumals are not only compiled and retained by feudal manors, but also are used by boroughs, which is the Valyrian term for any chartered town or larger settlement.