▁refer endum . ▁During ▁the ▁Free ▁State ▁it ▁was ▁also ▁the ▁O ire acht as ▁as ▁a ▁whole , ▁rather ▁than ▁the ▁D á il , ▁that ▁had ▁authority ▁to ▁commit ▁the ▁state ▁to ▁war , ▁although ▁this ▁distinction ▁was ▁not ▁significant ▁in ▁practice . ▁ ▁History ▁The ▁earliest ▁parliament ▁in ▁Ireland ▁was ▁the ▁Parliament ▁of ▁Ireland , ▁which ▁was ▁founded ▁in ▁the ▁th ir teenth ▁century ▁as ▁the ▁supre me ▁legisl ative ▁body ▁of ▁the ▁lord ship ▁of ▁Ireland ▁and ▁was ▁in ▁existence ▁until ▁ 1 8 0 1 . ▁This ▁parliament ▁govern ed ▁the ▁English - domin ated ▁part ▁of ▁Ireland , ▁which ▁at ▁first ▁was ▁limited ▁to ▁Dublin ▁and ▁surrounding ▁cities , ▁but ▁later ▁grew ▁to ▁include ▁the ▁entire ▁island . ▁But ▁the ▁Parliament ▁of ▁Ireland ▁was , ▁from ▁the ▁passage ▁of ▁Po yn ings ' ▁Law ▁( 1 4 9 4 ) ▁until ▁its ▁repe al ▁in ▁ 1 7 8 2 , ▁sub ordinate ▁to ▁the ▁Parliament ▁of ▁England , ▁and ▁later ▁Parliament ▁of ▁Great ▁Britain . ▁This ▁Parliament ▁consisted ▁of ▁the ▁King ▁of ▁Ireland , ▁who ▁was ▁the ▁same ▁person ▁as ▁the ▁King ▁of ▁England , ▁a ▁House ▁of ▁the ▁L ords ▁and ▁a ▁House ▁of ▁Commons . ▁Under ▁the ▁Act ▁of ▁Union ▁ 1 8 0 0 ▁the ▁separate ▁Kingdom s ▁of ▁Ireland ▁and ▁Great ▁Britain ▁were ▁merged ▁on ▁ 1 ▁January ▁ 1 8 0 1 , ▁to ▁form ▁the ▁United ▁Kingdom ▁of ▁Great ▁Britain ▁and ▁Ireland ▁and ▁the ▁Parliament ▁of ▁the ▁United ▁Kingdom .