The first meeting of a cross-border body comprising TDs, Senators and MLAs has taken place in Leinster House.
The idea for a North-South parliamentary association originated in the Good Friday Agreement in 1998.
Ceann Comhairle Sean Barrett described the meeting as "historic" in that it saw members of every party on the island sitting down to discuss matters of mutual interest.
The body is having discussions covering child protection issues and the future of the Ulster Canal.
Speaker of the Stormont Assembly William Hay said it was important that parliamentarians from both sides of the border could sit down together.
The meeting took place behind closed doors; Speaker Hay said this had always been agreed by all sides.
Mr Barrett said the assembly had to tread carefully on its first meeting and this had been achieved today.
However, the gathering will see DUP and Sinn Féin representatives discussing matters of mutual concern on a cross-border basis.
It is also the first formal forum for discussions involving the Oireachtas and the devolved Assembly.
The 48-member body, along with joint chairs Ceann Comhairle Seán Barrett and Stormont Speaker William Hay, will meet twice a year to consider areas of common interest.
The inaugural session took place in the Seanad chamber.
