Star Forts

The star plan was one originating in Italy, which spread to France and, in following, to the rest of Europe upon the invasion of the Italian peninsula by the French in the mid-sixteenth century. The plan was devised as a response to the beginning of the age of blackpowder, introduced by Charles V's mercenary troops and their portable cannons and bombards. These new weapons could strike the solid stone walls of castles and cause cracking and, in the case of particularly forceful projectiles, shatter holes in the wall or disrupt the overall structure. The European response to this was initially the replacement of stone with bricks, because the glued-particulate nature of the clay absorbed the cannonball without breaking, because the particles making up the bricks were able to be compressed under high force and did not facilitate cracks.

A notable change that accompanied the new building style was the use of low walls as opposed to the highest walls possible. These lower, far thicker walls presented less of a target and retained greater depth to absorb cannon, without having to add a significant amount of building material. This was also more practical because it did not require as drastic scaffolding, and thus the fortresses could be constructed more quickly.

Most visually striking about the star forts were the bastions added on all sides that would come to form the typically five-pointed star shape stereotypically associated with the style. These bastions were pointed and triangular in nature, and served to allow adjacent bastions to protect each other with cover fire in the event of an attack. The form also allowed for defense within multiple ranges as opposed to the previous floorplans, which were limited within several ranges. San Marcos was one of the earlier structures of this sort, and was thus only a four pointed star, with wide horizontal stretches between the corners, which were not as conveniently defended. At this point in time, castles tended to have rounded walls and to be based on the concentric-circles floorplan. The curved walls allowed for significantly less defense fire to be applied to any given point, although there was some modicum of fire available from any direction. The lack of focus, because arrows and guns could not be shot around a circular wall, led to the castle's inability to heavily attack a pointed assault. While these circular castles were an improvement upon the square model, with its massive blind spots on the corners, the star fort was an exceptional update.