…to keep the front part very rigid, a “busc” was added. This was a piece of wood, horn, whalebone, metal, or ivory that was thicker on top and tapered down. This was often beautifully decorated and inserted between the layers of linen and tied in by a lace.
(Left: Modern wooden busks; Right: Mary Countess Rivers in 1593 with stiffened body using tapered “busc”)