Initially, market towns most often grew up close to fortified places, such as castles or monasteries, not only to enjoy their protection, but also because large manorial households and monasteries generated demand for goods and services. Historians term these early market towns "prescriptive market towns" in that they may not have enjoyed any official sanction such as a charter, but were accorded market town status through custom and practice if they had been in existence prior to 1199. From an early stage, kings and administrators understood that a successful market town attracted people, generated revenue and would pay for the town's defences. In around the 12th century, European kings began granting charters to villages allowing them to hold markets on specific days.