Why is Ireland seperated into Northern Ireland and Republic of Ireland?

Question

Why is Ireland seperated into Northern Ireland and Republic of Ireland?

Answer 1

Because the British separated the island into two entities where in the 6 copunties in the North there werte a majority of British/Protestant settlers , so the Protestants in the North are protected by their British kin . And Ireland in the South where there was in the 26 counties a majority of Native Irish was created into Eire . Thats why the IRA and INLA fought tooth and nail to liberate Ulster from the British invader/settlers and reunite the entire Island of Ireland for the Native Irish .