by what century did plate armor become more common
Such medieval polearms as the halberd and the poleaxe were variants of the basic battle-axe form. Steel plate-armor covering almost all of a knight's body, and incorporating features specifically designed to defeat axe and sword blades, become more common in the late 14th and early 15th century. Its development led to a generation of hafted weapons with points that concentrated impact, either to penetrate steel plate or to damage the joints of articulated plate.