A residential tower is a medieval tower that was suitable for permanent use as a dwelling and at the same time also had defensive functions. It usually had only one high entrance. Residential towers were erected throughout Europe from the early to the late Middle Ages and represented - in contrast to a large castle complex - a relatively quick and inexpensive prototype of a fortified and befitting dwelling for knights. They were often additionally protected with palisade fences, moats or small ring walls (then also called tower castles). However, they could also be included in large castle complexes. Residential towers located in towns, especially in Italy, are called gender towers, which were often distinguished by their astonishing height. Later they were often capped to ridge height. Such towers based on the Italian model also existed in many German cities in the Middle Ages; preserved examples can be found mainly in Regensburg and Trier.