There were powerful Irish Peers in the House of Lords.
Most Irish Protestants opposed Home Rule, favoring continued union with the United Kingdom.
Most settlers were Scottish Calvinism who crossed the short passage from West Scotland to the country of Ulster in the North of Ireland.
While Protestants were a small minority in the South they became a majority in the North.
In 1919, the Irish War of Independence officially began.
The Government of Ireland Act was enacted in 1920, and the island was partitioned into Southern and Northern Ireland the following year, but Home Rule never came into effect in the South.On May 3, 1921 the Government of Ireland Act 1920 partitioned the island into two autonomous regions Northern Ireland (six northeastern counties) and Southern Ireland (the rest of the island).Afterwards, institutions and a government for Northern Ireland were quickly established.Meanwhile the institutions of Southern Ireland generally failed to function or take root as the large majority of Irish Members of Parliament gave their allegiance to Dáil Éireann as part of the Irish War of Independence.That war ultimately led to the Anglo-Irish Treaty which envisaged the establishment of an independent Dominion, the Irish Free State, provisionally for the entire island of Ireland.The official division of the country of Ireland into two separate regions – Northern and Southern Ireland – took place in May 1921, through an act passed by the British Parliament.The original intention was for both regions to remain within the United Kingdom, but the Irish War of Independence led to the south seceding from the UK in 1922, while Northern Ireland opted to remain.With attempts at this legislation having begun in 1886, the Government of Ireland Act of 1920 was the fourth try at establishing Home Rule in Ireland – that is, affording the country a certain amount of freedom to self-govern while retaining its position as part of the United Kingdom.Up to that point Ireland had been ruled by the UK Parliament via their administration at Dublin Castle, ever since the Irish Parliament was abolished through the Acts of Union 1800.The original intend had been to grant self-government to the whole island but protest from the North and the threat of violence resulted in what was effectively a partition plan.The South did not formally agree to partition, indeed Britain did not consult the whole people of Ireland on this issue and refused to take Ireland's case to the Paris Peace Conference even though the rights of small states and the right to self-determination was within its remit.