▁At ▁the ▁heart ▁of ▁these ▁arm ies ▁was ▁the ▁familia ▁reg is , ▁the ▁permanent ▁military ▁household ▁of ▁the ▁king , ▁which ▁was ▁supported ▁in ▁war ▁by ▁fe ud al ▁lev ies , ▁drawn ▁up ▁by ▁local ▁nobles ▁for ▁a ▁limited ▁period ▁of ▁service ▁during ▁a ▁campaign . ▁Mer cen aries ▁were ▁increasing ly ▁employed , ▁driving ▁up ▁the ▁cost ▁of ▁war fare , ▁and ▁ade qu ate ▁supplies ▁of ▁ready ▁c ash ▁became ▁essential ▁for ▁the ▁success ▁of ▁campaign s . ▁ ▁Naval ▁forces ▁played ▁an ▁important ▁role ▁during ▁the ▁Middle ▁A ges , ▁en abling ▁the ▁transport ation ▁of ▁troops ▁and ▁supplies , ▁ra ids ▁into ▁host ile ▁territory ▁and ▁attacks ▁on ▁enemy ▁fle ets . ▁English ▁naval ▁power ▁became ▁particularly ▁important ▁after ▁the ▁loss ▁of ▁Norm andy ▁in ▁ 1 2 0 4 , ▁which ▁turned ▁the ▁English ▁Channel ▁from ▁a ▁friendly ▁trans it ▁route ▁into ▁a ▁cont ested ▁and ▁critical ▁border ▁region . ▁ ▁Although ▁a ▁small ▁number ▁of ▁cast les ▁had ▁been ▁built ▁in ▁England ▁during ▁the ▁ 1 0 5 0 s , ▁after ▁the ▁con quest ▁the ▁Norm ans ▁began ▁to ▁build ▁tim ber ▁mot te ▁and ▁ba iley ▁and ▁ring work ▁cast les ▁in ▁large ▁numbers ▁to ▁control ▁their ▁newly ▁occupied ▁territ ories . ▁During ▁the ▁tw elf th ▁century ▁the ▁Norm ans ▁began ▁to ▁build ▁more ▁cast les ▁in ▁stone , ▁with ▁characteristic ▁square ▁keeps ▁that ▁supported ▁both ▁military ▁and ▁political ▁functions . ▁Royal ▁cast les ▁were ▁used ▁to ▁control ▁key ▁towns ▁and ▁for