Swiss Alpine Defense System

Timeline

1. 1291–1300Entries to the Schwyz and Uri valleys · SwitzerlandAfter the three cantons allied in 1291, facing Habsburg overlordship pressure, the cantons used the natural bottlenecks of Alpine gorges to set transverse barriers (Letzi) at valley mouths. Early barriers combined stone walls, ditches, and flanking high-ground observation, serving both defense against invasion and control of trade routes with toll collection.
2. 1300–1310Rotenturm · Canton of SchwyzSchwyz canton massively reinforced stone Letzi around Rotenturm and Altmatt, crossing the valley route with towers. Meanwhile places like Arth built double defense lines, including lakeside palisades and land stone walls (about 3.7 m high and 0.9 m thick) with ditches in front, forming a defense in depth.
3. 1310–1315Lake of the Four Forest Cantons and Morgarten · SwitzerlandNidwalden built lakeside palisade defenses at Stansstad, Buochs, Beckenried, and other points on Lake Lucerne to prevent landings. In the 1315 Battle of Morgarten, the three-canton allied force used the narrow passage and forested flanks together with the barrier system to ambush and heavily defeat Habsburg cavalry, validating mountain defense tactics.
4. 1315–1388Valley mouths on the Swiss Confederacy frontier · SwitzerlandAfter the Morgarten victory, the Letzi defense model spread to more valley mouths (such as Näfels) as the Confederacy expanded. Battles like Sempach (1386) and Näfels (1388) continued to embody the Swiss military tradition of using terrain and barriers to delay the enemy and engage in infantry close combat.