Who built castles and why? Where were most castles built?
Castles, for the most part, began to appear in the form of the Motte and Bailey (see next Q&A segment). The appearance of this type of castle coincides with the territories in which the Viking attacks were most prominent; therefore, strengthening the argument that castles were erected as a quick form of fortification against an enemy who lacked siege engines (Bradbury 51). Admittedly, castles were erected for defense, and in this capacity would simultaneously protect the villagers who lived within its borders and control the neighboring territories, serving as a combination command post, defensive fortification, judicial authority, and a symbol of power (Contamine 45-46). However, save for the M&B castles, the majority of the development of castles came in the years after the Viking raids subsided (Bradbury 52). It is, therefore, necessary to explore other reasons for which castles were built.
As the Carolingian Empire slowly succumbed to internal conflict--starting from the point of Charlemagne's death--the balance of power of the great nobles began its shift to include princes of royalty and, of more importance, counts and castellans. As Bradbury points out, "castles are the sign of the rise of these two groups....castles have more to do with internal social struggle in the west than with defence [sic] against external invasion" (52). It was due to this internal social-class struggle that the emergence of the castle was greatest in the Frankish heartlands (56) and this observation is strengthened by Contamine's statement that it was "the innumerable military vicissitudes which accompanied political action, the castles played an essential role. During the feudal period France was a country of castles, where a 'great stone civilisation [sic]' spread" (44).
With that having been said, it is still important to note that castles were,