John F Kennedy. Nelson Mandela. Bill Clinton. Tony Blair. And now, Volodymyr Zelensky.

The Ukrainian president's address to a joint Dáil and Seanad session is set to become the latest in a series of video-link speeches to parliaments across the world to ensure his country's voice is heard.

While internationally the speech itself is one of dozens the Ukrainian leader has given since Russia invaded his nation, and may therefore seem unexceptional, within Irish political life it's an entirely different prospect.

Acknowledging that fact is key to explaining the serious message today's event at Leinster House is intending to send.

Since the foundation of the Irish State, just 11 current or soon to be future foreign leaders have been handed centre stage in Ireland's parliament.

The honour is rare - and Volodymyr Zelensky's appearance indicates the serious nature of what is now taking place in Ukraine, and the potential consequences of the ongoing conflict.

John F Kennedy - The history maker

US presidential visits to Ireland are commonplace in the modern era, with five of the last six White House incumbents dusting off their finest green tie and family tree - and current president Joe Biden on record about his intention to visit soon.

But in 1963 it was different, meaning John F Kennedy's journey back to Ireland and invitation to Dáil Éireann was history making.

The Boston son of Irish emigrants came "home" in June while on the same European tour in which he told a German crowd "ich bin ein Berliner" - travelling to Limerick, his ancestral home in Dunganstown in Co Wexford - and ultimately Leinster House on 28 June 1963.

US president John F Kennedy on Dublin's O'Connell Street in 1963

His iconic Dáil appearance was the first time any foreign dignitary had spoken in the Dáil, and saw him emphasise the heartbreak of emigrants fleeing a land in conflict for safety abroad - a message which still resonates.

From the Archives: 'Prosperity is not enough'

President Kennedy left the Dáil with a quote from Irish poet George Bernard Shaw, saying: "Other peoples see things and say 'why'. But I dream things that never were, and say 'why not'."

Almost exactly five months later, he was shot dead in Dallas, his trip to Europe and Ireland being his final one abroad.

Ronald Regan - Cold War era

Two decades later, Republican president Ronald Reagan became the second foreign leader to be invited to speak at Leinster House - on 4 June, 1984.

As with most parts of life, second time around was not quite as innocently remembered, with president Reagan's appearance in the Dáil resulting in a walk-out by Workers Party TDs Tomás MacGiolla and Proinsias de Rossa, and left-leaning Independent TD Tony Gregory.

The incident did not put off the then White House incumbent, who like his predecessor John F Kennedy focussed on emphasising his Irish family links and discussed his perspective of the cold war stand-off at that time.

Nelson Mandela - Cry freedom

The subsequent years saw Ireland's parliamentary invitations move further afield, with Australian prime minister Bob Hawke visiting in October 1987 and French president Francois Mitterrand following suit in February 1988.

But it was the visit of someone who at the time was yet to become the leader of his country that caught the public's attention once more.

On 2 July 1990, Nelson Mandela - who five months earlier on 11 February 1990 had taken the final steps on the long walk to freedom while hand-in-hand with his then wife Winnie Mandela - came to Leinster House.

Nelson Mandela speaking in Dublin in 1990

In his speech, the future president of a post-apartheid South Africa who at the time was deputy leader of the African National Congress spoke of the violence perpetuated by the apartheid regime, saying it "condemned to the gallows" brave people, imprisoned others, "and driven some into exile" whose only crime was "to cry 'freedom'".

From the Archives: Nelson Mandela Dáil Address

Quoting the Irish poet William Butler Yeats, Mr Mandela said "too long a sacrifice can make a stone of the heart".

But, pointedly, he added that the only way to overcome this through "the love of the warm hearts the oppressor sought to turn to stone, the love of their country and people, and in the end, the love of humanity itself".

Bill Clinton and Tony Blair - The peace process

It was a point that mirrored the following decade in Ireland, with ceasefires, peace talks and ultimately a peace deal taking place in Northern Ireland during the 1990s.

And, while they were far from the only national and international leaders involved, the Dáil attendance in 1995 of US president Bill Clinton at the start of real talks and British prime minister Tony Blair in 1998 after the Good Friday Agreement was signed underlined the progress being made.

On 1 December 1995, Mr Clinton said his visit to Belfast had made it clear to him "the immense hope" the era could lead to lasting peace, which at the time was far from certain.

Bill Clinton told the Dáil: 'The people want peace, and they will have it'

Making the point clear, he described the scenes he saw after giving a speech to crowds at the lighting of the Belfast city hall Christmas tree lights, telling the Dáil: "The people want peace, and they will have it."

By Tony Blair's visit to Leinster House almost three years later on 28 November, 1998 that hope had turned to reality, after the signing of the Good Friday Agreement on 10 April that year.

Mr Blair's appearance in the Irish parliament was the first of any British prime minister, a record he poignantly noted, saying: "I feel profoundly the enormity of the honour you are bestowing upon me. Let us not under-estimate how far we have come, and let us agree that we have come too far to ever go back now."

Who else has spoken? - Brexit, the EU and the world

Among other foreign speakers to the Dáil have been Australian prime ministers Bob Hawke in October 1987, Paul Keating in September 1993 and John Howard in May 2006.

Similarly, then French president Francois Mitterrand addressed the Dáil and Seanad in February 1988 and German chancellor Helmut Kohl addressed the Dáil in October 1996 - both in their native languages.

US House speaker Nancy Pelosi addressed the Dáil and Seanad in 2019

On 18 April, 2019, the speaker of the US house of representatives Nancy Pelosi also appeared at an unofficial sitting of the Dáil and Seanad to again emphasis the need for the peace process to continue regardless of the impact of Brexit on Northern Ireland.

But the number of times foreign leaders have been invited to speak at Leinster House remains rare.

A reality that underlines the importance of the message being sent by Mr Zelensky's attendance in the home of Irish politics.