the border between northern Ireland and the republic

is one of the most contentious in the world

thousands have died over it

decided by politics not geography

its irregular shape looks odd

it divides roads

houses in one place

it even separates a church from its graveyard

for an outsider looking at the Irish border

it doesn't make very much sense

but it does have it to incurious logic

so what's the story behind it

and what really divides Ireland

even after 100 years

this border is still deeply sensitive

Ireland’s border was created in 1921

while northern Ireland remained in the United Kingdom

the south left

but to

understand why Ireland was divided in the first place

we need to go back in time

in the sixteen hundreds the British

who were mostly protestants

started colonizing catholic Ireland

they took control of the north

discriminating against Catholics and other dissenters

in 1798 it led to a major rebellion

it was crushed by the British

who decided to adopt a new policy

total control

in 1801

the whole of Ireland became part of the United Kingdom

for protestants in the north it was a huge victory

for Catholics in the south who wanted independence

it was a catastrophe

but it also brought a new opportunity

to influence the British government

there were no Irish MPs going to Westminster

and those people became very

significant players in British politics

Westminster became the stage

for the campaign for home rule for Ireland

with politicians arguing both sides of the debate

and back on the streets of Ireland tensions escalated

in 1916 pro independence Catholics

carried out an armed insurrection

that came to be known as the Easter rising

it triggered further revolution that turned into a war

for independence

with protestant paramilitary groups in the north

fighting to remain part of the United Kingdom

in 1921 the British government ended the war

signing a treaty that

gave Southern Ireland independence

the treaty was signed on December 21st

and Dublin showed its approval

with a colorful parade of gaily enthusiasm

but it wasn't a complete victory for the separatists

the British government

had decided to carve the country in two

while the northern

protestant communities

would remain part of the United Kingdom

the south would be free to rule itself

it radically redrew the map of the United Kingdom

and for the first time

an international border was drawn

between northern Ireland and the south

it was a very

simple and a very crude calculation

as to where the northern Irish border was drawn

it was about trying to have

as many protestants as possible in the north

and as few protestants as possible in the south

that's why the shape of this border

is so highly unusual

partition satisfied no one

Catholics in the south could now govern themselves

but their country had been split in two

protestants in the north had hoped the

whole of Ireland would stay in the United Kingdom

and there was one group that was put in an especially

intolerable position

Catholics in the north arguably lost the most here

they were trapped in a state which they didn't want

they were never

it seemed in 1921 ever going to be

sufficiently numerous to vote their way out of this

over 400,000 Catholics were now trapped on the

wrong side of the border

their plight would trigger decades of bloodshed

in the north anti catholic discrimination became rife

by the late 19 sixties

civil rights demonstrations in America

inspired northern Irish Catholics

to protest peacefully for equality

but police often used brutal force to crush the marches

and loyalist protestants targeted the protests

as well as holding their own marches

in 1969 a confrontation

at a protestant March

sparked days of clashes that spread across

northern Ireland

overwhelmed northern Ireland’s prime minister

asked the British government for help

British troops were sent in

it was the beginning of three

decades of violence in northern Ireland

now called the troubles

in 1972

British soldiers opened fire on catholic protesters

14 died and at least 15 were injured

it became known as bloody Sunday

I was fired on by the paratroopers

and yet parliamentary democracy was such

that I was not allowed to speak

the event radicalized angry Catholics

membership of republican paramilitary groups

such as the IRA swelled

and deadly attacks against protestants

and British troops increased

in my opinion

we cannot do with the Irish republican army

republican power militaries were able

to use that border to their advantage at various points

they could flee across that border

they were able to use it to store weapons

border infrastructure was itself a target as a

symbol of British rule and Ireland

in response

the British armed forces became a permanent presence

at the border

and established bases elsewhere in northern Ireland

the IRA argued they were fighting a military occupation

but loyalist northern Irish malicious

saw the border as protection

against a catholic majority

they attacked those they deemed republican sympathizers

we're going to tarnish turn on the Obama holocaust

a tit for tat campaign of violence began

three car bombs in quick succession

ripped through the village

just a few miles from Londonderry

over the 30 years of the troubles more than

3700 people were killed

many many more were injured

and most

of those who were killed and injured were civilians

as headlines of attacks and atrocities increased

global leaders attempted to promote peace

the history of northern Ireland has been written

in the blood of its children and their parents

in 1998 there was a breakthrough

today we can take a collective breath

and begin to blow away

that's hope the cobwebs of the past

the British and Irish governments and most

of the political parties in northern Ireland

came together

to sign a landmark deal

that became known as the good Friday agreement

the deal removed the hard border

between the two countries

and stated that if majorities in

both north and south wanted to reunite Ireland

they could

the following two decades were relatively stable

in northern Ireland until now

in 2016

the United Kingdom voted to leave the European union

it opted for a complete break

ending free movement of people and goods

as part of the UK

northern Ireland would also have to leave

but with the Republic of Ireland still a member

and the border between the two countries

now fairly open

there was a problem

as they were now governed by different rules

again

the obvious solution was to reestablish a hard border

a move no one wanted

the only other option

would be a de facto trade border in the Irish sea

separating northern Ireland from the rest of the UK

this proposal was called the northern Irish protocol

and it removed the need for a hard border

but northern Irish loyalists weren't happy

we are totally opposed to the protocol

we will neither accept it

nor will we work it

at the same time

increasing numbers of northern Irish

are welcoming unity with the south

there is this growing center grind of people

who may or may not be religious

people who have grown up in peace

who don't understand

the forces which drove northern Ireland into conflict

who don't identify with them

these changes might make a united Ireland more feasible

but they could also reignite old tensions in the north

one of the things which concerns

many people in northern

Ireland whatever their view and Irish unity

is that if we did

have a vote in fever of Irish unity

particularly a narrow vote in fever of Irish unity

that

that could precipitate violence in northern Ireland

and as difficult and fraught as the Brexit process was

in the and rest of the UK

there was never any serious prospect of

riots on the streets of London of people being killed

of bombs going off

in northern Ireland

that would be a very real possibility

and perhaps a probability

thanks for watching

to read more of the economist's coverage of

northern Ireland and the Irish border