He was the IRA commander who took arms against the British only to shake the hands of Queen Elizabeth as a political leader in Northern Ireland.
A former butcher from the Bogside in Derry, a man of action during the street fighting of the 1970s, he ended up toasting the Queen at Windsor Castle after a long career of peace-making.
The decision by Martin McGuinness to bow out of frontline politics in the North was not surprising but is a seismic event.
His journey from the streets of the Bogside to the office of Deputy First Minister in Stormont, the traditional home of Ulster Unionism, was by any standard, remarkable, as described by former President Mary McAleese last night.
Describing his departure from the political arena as “desperately sad”, Ms McAleese said McGuinness’ retirement represented a huge loss to politics in the North.
In 1972, the thought of the British monarch greeting the man who helped lead the Provisionals in a bloody campaign against British rule in Northern Ireland would have been unbelievable.
He turned to republicanism after witnessing the 1960s government repression of the nationalist community and its failure to prevent the escalating violence that destroyed the civil rights movement.
When the Provisional IRA began to emerge (albeit in small numbers) in key nationalist areas in 1969 and 1970, McGuinness joined and rose through its newly formed ranks.
In 1971, he became the 21-year-old commander of “Free Derry” and appeared at a Provisional IRA press conference where the new leadership offered to talk peace.
The Saville Inquiry into Bloody Sunday said he “probably” carried a sub-machine gun during the massacre of 14 unarmed civil rights protesters by soldiers in Derry.
Unlike others, McGuinness never denied his past. He admitted to being second-in-command of the IRA that day.
In 1973 he was convicted by the Republic of Ireland’s Special Criminal Court after being arrested near a car containing explosives and ammunition.
At his 1973 conviction, McGuinness said: “We have fought against the killing of our people. I am a member of Óglaigh na hÉireann (IRA) and very, very proud of it.”
After his release, and another conviction in the Republic for IRA membership, he became increasingly prominent in Sinn Fein, eventually becoming its best known face after Gerry Adams.
He was in contact with British intelligence indirectly during the hunger strikes in the early 1980s, and again in the early 1990s.
He became MP for Mid Ulster in 1997 but in line with Sinn Fein’s abstentionist policy from Westminster, he took his expenses but not the seat.
McGuinness was Sinn Fein’s chief negotiator of the 1998 Good Friday peace agreement which ended violence, secured IRA arms decommissioning in 2005 and shared government with former enemies in Belfast as deputy first minister.
Following election to the new Northern Ireland Assembly, Sinn Fein nominated McGuinness to become education minister. That sparked fury from some unionists, though Mr McGuinness insisted he would govern for all children.
Against the odds, McGuinness and the great enemy of republicanism Ian Paisley forged a decent working relationship and a warm bond developed between the two men.
They were dubbed “the Chuckle Brothers” but it is said the two never shook hands.
In December 2007, while visiting US president George W Bush at the White House with Paisley, McGuinness said: “Up until the 26th of March this year, Ian Paisley and I never had a conversation about anything — not even about the weather — and now we have worked very closely together over the last seven months and there’s been no angry words between us.
“This shows we are set for a new course.”
The Good Friday Agreement proved difficult to implement and was followed by the St Andrew’s Agreement in 2006.
Sinn Fein ambitions such as a bill of rights for Northern Ireland and an Irish language act are still unfulfilled.
After Paisley’s retirement, McGuinness endured a much tougher time with subsequent DUP leaders, Peter Robinson and more recently Arlene Foster at the top of the power-sharing executive in Stormont.
He unsuccessfully ran to be Irish President in 2011, but it was his attack on fellow candidate Sean Gallagher in a key television debate which saw the latter’s campaign capitulate and Michael D Higgins elected.
His IRA past dogged him throughout the campaign with then minister Phil Hogan asking the question: “Do we really want a terrorist in the Áras?”
Now in 2017, McGuinness has had his political journey ended by serious illness.
This became evident to most only 10 days ago when he resigned his position as deputy first minister over the Renewable Housing Incentive scandal.
The frail figure and weak voice that came out of our television screens shocked many who saw McGuinness, the icon, so familiar to so many for so long, diminished so dramatically.
Under the power-sharing arrangements, he took the first minister with him, ending a decade of testy coalition government with the DUP and forcing an election.
But his refusal at that stage to clarify his own intentions led many to conclude his time was coming to an end.
He confirmed those suspicions last night.
“Last year, Gerry Adams and I confirmed that we had a plan in place for transition to a new leadership. For my part, it was my intention to step aside in May this year which would have marked 10 years since I entered government with Ian Paisley as joint leader of the northern Executive.
"Unfortunately, my health and the current crisis have overtaken this time-frame and I am stepping down from my role to make way for a new leader of Sinn Féin in the North,” he said.
He said his “obvious health issues” have forced him to be open and honest with his friends and colleagues in Sinn Féin, with the electorate of Foyle.
“Unfortunately, I am not physically able to continue in my current role and have therefore decided to make way for a new leader. This election is the right time for me to move aside so I will not seek re-election to the Assembly,” he said.
So as he exits stage left, McGuinness’ legacy will loom large over not just republicanism but Northern Ireland politics in general.
His rejection of the bomb in favour of the ballot was truly significant and his ability to work with bitter enemies like Paisley and Robinson illustrates the extent of his abilities.
He retires without his dream of a united Ireland being fulfilled during his tenure and strong doubts remain among some republicans about what they have gained through entering Stormont.
But his contribution to peace on this island will be long remembered.