SHORT ANSWER - The Island of Ireland, part of the British Isles, contains two countries - 1. Republic of Ireland (towards the south) which is "Catholic" and 2. Part of the nation known as "The United Kingdom of Great Britain and Northern Ireland" towards the north, which is Protestant.
The Republic of Ireland is an autonomous nation in the European Union whilst Northern Ireland is an enigmatic plot of land nominally governed by the British Government. LONG ANSWER - The real Long Answer would be just too too long! So this is a shortened "Long Answer" The island of Ireland was never occupied by the Romans and was originally (ie pre-Roman) populated by peoples known as the Celts who occupied the western edges of Europe.
(England was originally populated by "Britons" and Scotland by "Picts") After the Romans left England/Wales (which they called Britannia) European people (mainly Angles and Saxons - hence "Angland" or "England") invaded and pushed the Britons to the West. But Ireland remained occupied almost exclusively by the Celts. Lots happened to the population in mainland Britain (now known as Scotland, England, Wales) over the next 1,000 years or so but very little happened on the island of Ireland, which remained populated by Celts (with a little immigration of Vikings).
Some of these Celts (who called themselves "Scots") began to migrate from North parts of Ireland to South West Caledonia (the Roman name for modern Scotland) about 600 AD and spread across "Pictland" until, in the ninth century, the nation of Scotland was formed. Britain (Scotland, England, Wales) became Catholic and then in about 1500 became Protestant. Ireland became Catholic and remained Catholic.
The Scots from Ireland, who migrated to Caledonia, brought religion with them (Catholicism). They later converted to Protestantism. These Scots then migrated back from "Scotland" (as it was then known) to Northern parts of Ireland, bringing Protestantism with them.
Therefore the Northern parts of the island of Ireland became Protestant. Ireland, the nation of the whole of the island called Ireland, was occupied by the English (later known as British). The peoples of Ireland never took to their occupiers, and in the first couple decades of the twentieth century fought a guerrilla war against the occupiers of Ireland and finally displaced them in about 1917.
The Republic of Ireland was finally formed in 1949. However! In the northern parts of the island of Ireland, the people were mainly of Scottish extraction (having emigrated back from Scotland over previous centuries) and were Protestant.
They felt allegiance to the British nation and were religiously opposed to Catholicism. They refused to join the Irish Free State and never joined the Republic of Ireland. Instead they joined the United Kingdom, thus creating the "Untied Kingdom of Great Britain and Northern Ireland" Over the later part of the twentieth century, there has been a guerrilla war by some extremists to re-unite Ireland into one nation.
This has been resisted by the current population and supported by the British government who believe the decision belongs to the current populous of the area and not the decision of the whole of Ireland - to be fair, the government of the Republic of Ireland also support this resolution. The situation is now in a state of tender peace while slow diplomacy is working to find a long term solution to this very real human dilemma. Hope this helps understand the dilemma facing all the peoples of the island of Ireland and the two governments who are trying to resolve the matter as fairly as possible.
Northern Ireland is a part of the United Kingdom in the North-east of the island of Ireland whereas republic of Ireland is a sovereign state in Europe occupying about five to sixths of the island of Ireland.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.