The National Archives define 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.
[5] Custumals of the Manor of Cockerham, written in Latin in 1326–1327, regulated usage of all resources of the country: peat fuel, salt, sheep, goats, horses, cattle and shoreline mussels.
[16] Custumals were compiled for a practical purpose: to guide, and even educate, successive generations of civic officials tasked with keeping law and order within their boroughs.
Even though town clerks and scribes inherited these registers as part of their duties to preserve local custom, they were also obligated to modify and add to them to respond to changing interests and the needs of their communities.
The study of borough customs primarily flourished in the early twentieth century, when both historians and amateur antiquarians began to take a keen interest in the constitutional origins of the English law.