On May 3, 1921, Northern Ireland officially took over, while the division of the Irish island was legal.
The decision to split Ireland in two decades of turmoil between nationalists seeking independence from British rule and unionists wanting to stay in the UK.
The border divides the 32 islands into two separate jurisdictions, six of the northeastern counties becoming Northern Ireland, which is still part of the United Kingdom.
26 other territories became Irish independent states. But now the Republic of Ireland
As Northern Ireland marks the centenary, BBC News NI looks back at the earliest days of the Irish border and how it decided the conflicting 310 miles (500 km) of the route.
Why does the partition happen?
The partitioning was seen by the British government as a compromise solution.
Nationalists have been campaigning for decades for the “Home Rule” to seek parliament in Dublin.
But unionists, mostly Protestants, do not want to be ruled out of Dublin.
Unions hold a majority in the northeastern province of Ulster. But in Ireland overall, they outnumber most of the nationalists, who are Catholic.
In 1916, when Britain was distracted by World War I, Ireland was watched in Ireland when nationalists staged a short but violent rebellion – an escalating Easter season.
The riots were defeated within days. But the action by British rebel leaders has sparked sympathy and support for the nationalist cause.
Easter Rising was widely viewed as the catalyst of the later Irish War of Independence, which began in 1974. Fri 1919
The following year, the British government decided to divide Ireland by proposing a parliament in Dublin and giving it to their own parliamentarians in Belfast.
Why are the borders drawn where it is?
Ulster Province is made up of nine counties. But only six are included in Northern Ireland’s legal boundaries.
That is because trade union leaders are concerned about anti-nationalism in discrimination and believe they need a majority to remain in power.
The Ulster Unionist Council admitted it would mean sacrificing the counties of Donegal, Cavan and Monaghan, each with a majority of Catholics, most of whom would vote for the nationalists.
The Irish Government Act of 1920 paved the way for Sir James Craig to lead a parliament with a new controlled union in Belfast, and he was elected as Northern Ireland’s first Prime Minister.
The Act set the border, stating: “Northern Ireland will consist of the parliamentary districts of Antrim, Armagh, Down, Fermanagh, Londonderry and Tyrone and the parliamentary districts of Belfast and Londonderry.”
The same act was also enacted for a separate parliament in Dublin. But at that stage, the house rules that Britain sanctions were no longer enough for Ireland’s revolutionary leaders.
In early 1919 they formed their own parliament and were waging a war for full independence.
How do people feel about the border?
Nationalist groups on the north and south of the border are furious by the partition and continue to campaign for independence for the entire island.
Many unionists were bitterly disappointed, especially those living in the south, and awoke to an uncertain future on May 3, 1921.
Craig’s six-district reconciliation angered many union supporters, historian Cormac Moore.
“Monaghan, Cavan and Donegal unions and Protestants were disgusted by the Ulster Unionist Council’s decision to abandon them as they had seen, and many of them left the Ulster Unionist Council for this reason.”
Is the border border permanently fixed?
No, when the border was first set, it was not clear how long it would last, or if its position would change in favor of trade unions or nationalists.
In fact, six months after the division of the Ireland border route has been put forward for negotiations.
The talks are in the form of a border commission, a three-person committee appointed to examine the borderline and decide whether it is in the right place.
Of course, for the nationalists, there aren’t any acceptable borders in Ireland. But some Irish leaders saw an opportunity on the commission to gain more territory for the Irish Free State.
The Boundary Commission is the result of the peace treaty that ended Ireland’s War of Independence in 1971. Fri 1921
Article 12 of the treaty available to the border commission to review existing borders.
Irish Delegation “It is innocently believed that this will lead to a myriad of lands that come to the Free State,” Cormacmoor said.
Why didn’t the border change happen?
The appointment of the Boundary Commission was delayed until 2018. Fri 1924, partly as a result of the outbreak of the Irish Civil War.
That three-year delay took a toll on nationalism – giving it time for existing borders, and the two economies were starting to differ.
But the action The “barricade,” according to Cormac Moore, was a decision by the independent state government to build a customs house along the border in 2017. Fri 1923
He argues that this leads to “A more tangible partition”
“It affects people on a daily basis more than what has happened before, and yes, it stabilizes borders in many ways.”
The three commissioners should have British chairs Richard Feetham and Belfast and Dublin government appointees.
But Belfast declined to nominate a commander, so the British government appointed a prestigious trade unionist to represent Northern Ireland’s interests.
How does the border commission decide?
The expeditionary surveyed border areas and consulted residents. But many historians agree that the ambiguous wording of the Anglo-Irish Treaty allowed the British president to interpret his work as he saw fit.
Article 12 of the treaty specifies the Commission. “It must be determined based on the wishes of its residents as to be in harmony with the economic and geographic conditions between Northern Ireland and the rest of Ireland.”
Nationalists believe “The desire of the residents” means, at the very least, most areas of border nationalism are transferred to independent states, according to political geographer Kieran Rankin.
He added that the unions “I want to focus on phrases that meet economic and geographic conditions”, with the belief that this will help Northern Ireland to keep it intact.
The Commission clearly supports economic factors, especially considering large, nationalistic cities such as Newry County Downs.
Newry is an important city for trade and transportation and “About three-quarters of the population reportedly enjoyed moving to an independent state,” according to Rankin.
The commission looked at Newry’s port revenues, coal supply infrastructure, and decided the city was too important for Northern Ireland’s linen industry to move south.
“This is a typical case study of economic and geographic conditions that influence residents’ wishes,” Rankin argues.
Only a small number of border villages, including Crossmaglen, Forkhill and Jonesborough in County Armagh, are recommended to be moved to the Free State.
But no big city has made a transfer list, hoping to have a Catholic majority in places like Strabane, County Tyrone.
What is the reaction to the Boundary Commission proposal?
Under the actual guidance of the Free State Border Commission, 282 square miles will be obtained.
But it would surrender 78 square miles to Northern Ireland, much of it around Donegal in the east.
The trade union group welcomed the results. But the Irish government was frightened.
Under a new border agreement signed in December 1925, the three governments agreed to revoke the commission’s powers and keep the borders where they were.
The Commission’s report was preserved and was not made public until 2016. Year 1969
What is the position of the border today?
A century after Northern Ireland’s boundaries were established in the Irish Government Act, the route of the border remained unchanged.
However, the area around the border has seen a lot of changes.
In the later years of the 20th century, it became a heavy military zone during the issue in Northern Ireland.
In more than 30 years of violence, the border has been trapped by British military checkpoints and is the site of regular IRA attacks.
In 1993, customs were removed as the European single market went into effect.
When the UK leaves the EU on 31 January 2020, the Ireland border becomes the UK’s only land border with the EU.
In order to avoid re-assigning a “solid border” to customs on Ireland, the British Government agreed to instead give the Irish Sea border.
The Brexit debate has galvanized nationalists to call for a referendum on unification of Ireland – but the power to call a poll on the border rests with Northern Ireland’s UK foreign minister.
Trade unions opposed the move and Prime Minister Boris Johnson said he did not see any Northern Ireland minister consider border surveys for the “government of the country”. “A very long time to come”
The opinion poll does not suggest that the vast majority of Northern Ireland support the elimination of borders that occurred a century ago.