Militarized snowflakes: The accidental beauty of Renaissance star forts

Summary

War is hell. But war is also geometry. And geometry can be quite beautiful. Prime examples of that disturbing paradox are the so-called star forts that proliferated throughout Renaissance Europe.Seen from above, these bastioned fortifications resemble elaborate ornamental diagrams, or perhaps even sacred mandalas. Yet their snowflake-like beauty was unintended. These were machines of war, developed from a mathematical attempt to solve a practical military problem: how to defend an army or a city from enemy artillery.Typical star-shaped fortification from Jean Errard’s influential 1596 treatise. (Credit: Jean Errard, public domain) Foundational to fortification theory was Jean Errard’s 1594 treatise La fortification réduicte en art et démonstrée, in which the French mathematician and engineer used geometry to formalize military architecture, helping to transform fort-building from a traditional craft into a discipline grounded in mathematics.The resulting star forts (so called because of their multiple fortified extrusions) solved a technological crisis. Medieval fortresses, built to withstand ladders, catapults, and siege engines, were no match for gunpowder-powered artillery, the 15th century’s major military innovation. A cannon could easily take out vertical masonry walls that had stood unconquered for centuries.Fort Bourtange, a fortified village in the Dutch province of Groningen. (Credit: Wikimedia Commons, CC BY-SA 3.0) Military engineers resorted to building lower, thicker ramparts, backed by earth, and sought to eliminate blind spots by building angular bastions — the aforementioned extrusions. Star fortifications started in Italy, were perfected in France (especially by the prolific Vauban), and dominated the European military scene for the entire 17th and 18th centuries, giving Europe’s strategic cities and landscapes a distinctive architectural look.Despite their sophistication, star forts eventually became obsolete, undone by the very problem they once ...