The theory of the Blockhouse defense system goes back (in some form) to the late 14th Century. They were ideally constructed and used as a strong point to be used against an enemy which did not have access to siege equipment and cannon (in later times). Constructed of block stone, they were stylized versions of free standing Donjons and Keeps. No exterior defensive walls were attached. Blockhouses could be a centralized structure for a small garrison of a village or town, and when used – were often the only form of defense available.
Shaping was varied with Rounded, Rectangular or Squared. In addition to stone, wooden Blockhouses were also constructed – and were a popular defense style when European powers began to expand their colonies to The New World. Blockhouses could be quite elaborate in style – in some cases being large enough to feature multiple levels. In later construction attempts, smaller cannon emplacements could be incorporated. Blockhouses could (and often were) constructed in pairs. They were a popular defensive structure during The English Civil War.