What gathers Protestantism and Catholicism is that they both are branches of the same religion. However, this is as far as their similarity goes. They worship the same God, but their principles are completely different. Five hundred years after the Reformation and the split of Protestantism from the Catholic Church, the contempt and hatred between Catholicism and Protestantism are still valid today.
The history of Northern Ireland can be traced back to the 17th century when the English managed to subdue the island after quenching a number of rebellions. The land of the Irish was colonized by English and Scottish Protestants banishing the predominantly Catholic people in the region.
Later on, at the start of the 19th century in the 1800s, the north and the south areas grew further apart due to economic differences. The north had more luxurious lifestyle as industry and manufacturing were on the rise. In the south, the unequal distribution of land and resources led to low standard of living for Catholics as Protestants owned most of the land there.