By the twelfth century urban castle towns and cities were well established, their function was for economical, social, ecclesiastical and fortification.
After the Norman Conquest fortifications such as castles were the prime concern. Prior to this period towns had been thriving, however, the new onslaught that took place caused destruction to many of the original towns. Whole areas were obliterated to make way for the new Norman castles, one such example is Winchester where churches and streets were destroyed to facilitate the development of the new town. This practice was not unusual during this period of unrest, fortifications were imperative, old made way for new.
Some churches however, managed to survive, incorporated within the walls of the new castle. Such places as Oxford, Dover, Hastings, Pevensey, Leicester and Warwick to name just a few.
As these new developments took place the castles encompassed the towns within their walls and what could not be placed inside was added to the outside structure of the perimeter wall for added security.
The Norman towns built between 1066 and 1140 numbered 47 in England and approximately 20 in Wales. The majority of these were attached to royal or Baronial Castles. This concept of town building was a new feature bought to England by the conquest, a practice commonly used in Normandy prior to this time.
The effective running of the castle led to a powerful growth within the urban town, resources were needed to equip and efficiently run such establishments, food had to be grown and goods needed to be made, therefor many people were employed within it's walls.
However, not all towns were the result of castles, in some cases the castle was built around the already well positioned established town. It is believed that Thetford and Arundal could have been two of these types of 'castle towns' and that the castle was post urban town.
The fortifications of the castle surrounding the main area of the town, and the importance of the administrative powers, led the towns to grow in strength. These military centres were necessary fortifications, allowing security against uprisings.
This arrangement was no different in Europe, in fact castles were built as fortifications to house military requirements as far back as the fifth century.
These castles, or military command centres, were originally places of administration, they took on the purpose of a garrison but very soon became the seat of authority were financial and judicial authority took place.