Atower castle is a smallcastle that mainly consists of afortified tower or a tower-like structure that is built on natural ground. It is thus different from themotte-and-bailey castle, which it may resemble, but whose main defensive structure is built on amotte or artificial hill. The tower castle is occasionally also described as a tower house castle or atower house.
Sometimes, during the development of a castle, it might be converted from a tower castle to a motte-and-bailey type, if the initial, ground level site is later remodelled by the construction of an artificial mound for thekeep orBergfried. The habitable but also fortified tower castle became the permanent private residence of numerous lords during the 11th and 12th centuries.
Since many tower castles had at least a few additional structures such as acurtain wall, often only a few metres long, its overlap with an "ordinary" castle is fluid, as is its transition to thefortified house.
