As has been previously discussed with such Articles as “Crown” and “Horn” Work, Tenailles, Caponiers and of course Bastions – all these were components of a type of late Medieval Defensive structure known as The “Star” Fort. The next “evolutionary” step in Castle and Fortifications, such structures were seen first on Italy around the 15th Century. As was determined with the advent of Gunpowder and early Artillery, the traditional design of The Medieval Castle, began to become extinct. Early Artillery Rounds (at first rounded and shaped Stone, followed by lead or iron), could easily destroy the stone and rock masonry of a Castle perimeter wall. The development of The Star Fort incorporated many of the traditional Castle building techniques, but with more refinements to accommodate Artillery attack and defense. Star Forts were large and wide foundation structures , that could include either a single “Level” or multiples built upon each other. Each spacing between Levels were filled in by Water Moats.
The foundation pattern of either a Hexagon or Pentagon was chosen. With multiple Levels, these sharp and obtuse angles were placed overlapping, thus – from higher elevations, the foundation resembled a “Star” shape. This was important in the overall defensive design of The Fort. Levels facing opposing directions were often supported by lighter Caponiers or Bastions at their bisecting points. Thus overlapping defensive area between such support Towers was known as a “Dead Space” or “Kill Zone”. Assaulting Infantry would be forced to contend with the spacings (near walks they could not otherwise scale or ascend). Archers, Riflemen and Artillery could be brought to bear on both Flanks, leaving no course but retreat….or annihilation. Although most successive Star Fort Levels used Moated Spacings, some only featured earth. Into these designs were incorporated smaller defensive structures, almost “Castle-like” in design. In terms of overall construction, Star Forts were constructed of Brick, reinforced by hundreds of tons of earth. Brick did not shatter as Stone did when exposed to Solid Shot (but absorbed much of the impact).
The overall layout of the Star Fort affords a complete, almost “panoramic” view of a battlefield or contested area. Enemy Troop Formations and advancements. In addition, Soldiers firing from a Star Fort were given unlimited access to bring their fire into any on-going direction, with relative safety. The eventual end of the traditional Star Fort came with the development of both Explosive Shells and High Velocity Field Mortars. Unlike most Artillery , which features limited elevation, The Heavy Mortar was designed to have a much higher and steeper trajectory, allowing an Explosive Shell to arch over a Star Fort Wall and detonate inside. Despite this, Star Forts would remain among the last major innovation in Fortress design for Centuries. The English “Device Fort”, grew from The Star design – as so it was adopted by Spain as a dominate form of Colonial Defensive System. Examples survived into the early to mid-19th Century in America, with variations used.