. ▁The ▁success ▁of ▁this ▁Community ▁led ▁to ▁the ▁desire ▁to ▁create ▁more , ▁but ▁attempts ▁at ▁creating ▁a ▁European ▁Def ence ▁Community ▁and ▁a ▁European ▁Political ▁Community ▁failed ▁leading ▁to ▁a ▁return ▁to ▁economic ▁matters . ▁In ▁ 1 9 5 7 , ▁the ▁E A EC ▁and ▁E EC ▁were ▁created ▁by ▁the ▁Tre aties ▁of ▁Rome . ▁They ▁were ▁to ▁share ▁some ▁of ▁the ▁institutions ▁of ▁the ▁EC SC ▁but ▁have ▁separate ▁executive ▁structures . ▁ ▁The ▁EC SC ' s ▁aim ▁was ▁to ▁combine ▁the ▁coal ▁and ▁steel ▁indust ries ▁of ▁its ▁members ▁to ▁create ▁a ▁single ▁market ▁in ▁those ▁resources . ▁It ▁was ▁intended ▁that ▁this ▁would ▁increase ▁prosper ity ▁and ▁decrease ▁the ▁risk ▁of ▁these ▁countries ▁going ▁to ▁war ▁through ▁the ▁process ▁of ▁European ▁integration . ▁The ▁E A EC ▁was ▁working ▁on ▁nuclear ▁energy ▁co - operation ▁between ▁the ▁members . ▁The ▁E EC ▁was ▁to ▁create ▁a ▁custom s ▁union ▁and ▁general ▁economic ▁co - operation . ▁It ▁later ▁led ▁to ▁the ▁creation ▁of ▁a ▁European ▁single ▁market . ▁ ▁The ▁E EC ▁became ▁the ▁European ▁Community ▁pill ar ▁of ▁the ▁EU , ▁with ▁the ▁EC SC ▁and ▁E A EC ▁continu ing ▁in ▁a ▁similar ▁sub ordinate ▁position , ▁existing ▁separately ▁in ▁a ▁legal ▁sense ▁but ▁govern ed ▁by ▁the ▁institutions ▁of ▁the ▁EU ▁as ▁if ▁they ▁were ▁its ▁own . ▁The ▁EC SC ' s ▁treat y ▁had ▁a ▁ 5 0 - year ▁limit ▁and ▁thus ▁exp ired ▁in ▁ 2 0