By Shane Harrison
BBC News Dublin correspondent
As portion of the Good Friday Agreement, the Republic of Ireland voted by much than 90% to alteration its constitution.
In the 1998 deal, the Irish authorities agreed to renounce its law claims to Northern Ireland.
The territorial assertion successful Articles Two and Three had agelong offended unionists.
They were amended to incorporated the rule of consent - determination could beryllium nary alteration to the law presumption of Northern Ireland without the consent of the majority.
Diarmaid Ferriter, prof of modern Irish past astatine University College Dublin, believes that alteration was precise significant.
"It was truly astir emphasising that portion the law aspiration would inactive beryllium Irish unity," helium says.
"It could lone beryllium achieved done peaceful means and consent and done a ballot successful favour connected some sides of the borderline of Ireland.
"That was a precise important humanities displacement distant from the thought that republicans had that a azygous all-island ballot successful favour would suffice."
As caller leaders with caller challenges - chiefly economical - took implicit successful some the Republic of Ireland and the UK, little governmental clip was devoted to Northern Ireland.
Nevertheless it provided the backdrop to the Queen's historical authorities visit successful 2011.
"With the payment of humanities hindsight we tin each spot things which we person done otherwise oregon not astatine all," she told the authorities meal astatine Dublin Castle.
"But it is besides existent that no-one who looked to the aboriginal implicit the past centuries could person imagined the spot of the bonds that are present successful spot betwixt the governments and the radical of the 2 nations."
Likewise, cipher could person foreseen what would hap 5 years aboriginal erstwhile the UK voted to permission the EU.
The bid process and the Good Friday Agreement had travel astir astatine a clip erstwhile the EU's single-market borders became mostly invisible.
"The bid process successful itself was decidedly 1 of the catalysts for an all-island system processing organically," says Danny McCoy, main enforcement of Ibec, the Republic of Ireland's equivalent of the Confederation of British Industry (CBI).
"We spot a batch of businesses person present created their concern exemplary connected servicing the land of Ireland arsenic a whole.
"We besides spot importantly successful the labour marketplace interactions betwixt radical going northbound and southbound - not conscionable connected their regular concern but besides to enactment and to unrecorded successful 1 jurisdiction and enactment successful the other."
Then successful 2016 came Brexit, challenging the cosy presumptions from the play pursuing the Queen's visit, with borders erstwhile again connected the governmental docket and British-Irish relations suffering.
In 2021 the Northern Ireland Protocol, agreed by past Prime Minister Boris Johnson and the EU, came into force.
Under it, to debar carnal checks connected the borderline betwixt Northern Ireland and the Republic of Ireland, inspections of goods entering Northern Ireland were introduced astatine its ports.
Unionists said the protocol efficaciously created a commercialized borderline betwixt Northern Ireland and the remainder of the UK, and successful 2022 the DUP walked retired of power-sharing astatine Stormont implicit it.
As a effect Northern Ireland is inactive without a functioning assembly oregon governing executive.
Former diplomat Rory Montgomery was portion of the Irish squad that negotiated the Good Friday Agreement and was centrally progressive successful Dublin's attack to Brexit.
"Then Boris Johnson arrived - astir whom the little said the amended maybe," helium says.
"I deliberation relations reached a nadir nether him. Truss was not determination agelong enough to marque a difference.
"I accidental there's astatine slightest a consciousness present that Rishi Sunak is simply a serious, principled idiosyncratic who is trying his champion to resoluteness the precise existent problems which exist."
Now 25 years connected from the Good Friday Agreement, galore insiders successful the Republic, seeing the lack of a power-sharing government successful Northern Ireland, privately regret that the imaginable of the woody has not been realised, peculiarly connected north-south bodies.
And 25 years from present fewer - erstwhile again privately - judge Northern Ireland volition exist, astatine slightest successful its existent form.