Which is the relationship between town and fortification? In a traditional perspective this has largely been considered a question of defense of the civilian population. However, this factor, though certainly important in several cases, cannot be seen as the only relevant factor addressing the problem. There are also other traditional explanations. One of these relates to questions of paying custom for selling and buying items. The fortified enclosure would make control of payment easier. A third factor, also frequently mentioned has to do with general control of a population inside the walls, i.e. controlling movement. These factors, but also several others, will be briefly discussed in relation to a set of primary examples from the Swedish realm, but also certain examples beyond the Swedish context, mainly taken from the Mediterranean macro-region. Most certainly, the relative relevance of various factors is not always the same, and this variability may be of major importance when addressing major fortification. Accepting for variability will allow us to start to understand better certain general problems, and will illustrate the importance of looking closer at the evidence (in form of texts, drawings, tangible remains, etc.)