For many years, leading unionists have labelled Martin McGuinness a member of the IRA's Army Council and, on one occasion, the "IRA godfather of godfathers".
Mr McGuiness will say he ordered IRA members not to shoot
Whatever the accusations, what is certain is that, along with Gerry Adams, he has been one of the most influential figures within the modern Irish republican movement, driving its development of a political strategy at the height of the Trouble's worst violence - and leading the party's devolution negotiations.
The one-time IRA commander went from the riots of the Bogside during the 1970s to the very heart of government, having become one of Sinn Fein's two ministers in the first power-sharing deal.
Those early days of his republican career are never far away in the popular mind of Northern Ireland.
So it's not in the least bit surprising that his 2003 appearance before the Bloody Sunday Inquiry, to talk voluntarily about the IRA's activities, became one of the most eagerly awaited moments of the peace process.
Mr McGuinness says that 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, Mr McGuinness joined and rose through its newly formed ranks.
In 1971, it is thought 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.
In May 2001 he became the most important member of the modern Republican movement to reveal his role when he confirmed that he would be telling the Bloody Sunday inquiry that he was second-in-command of the IRA in the city at the time of the tragedy.
During the 1970s he avoided internment - but not trial for terrorism related offences in the Republic.
At his 1973 conviction, Martin McGuinness said: "We have fought against the killing of our people. I am a member of Oglaigh na Eireann (IRA) and very, very proud of it."
Since then, Mr McGuinness has remained at the forefront of the republican movement.
His first meeting with British politicians came in July 1972 when the Provisional leadership was secretly taken to London for what would turn out to be failed talks with the government.
He was elected to the short-lived assembly of the early 1980s and by the middle of the decade, he and Mr Adams had stamped their authority across the bulk of the movement. It was during this period that republicans pursued a twin policy of a violent campaign by the IRA and a growing political movement headed by Sinn Fein.
But ultimately, the political strategy grew increasingly important to the republican movement. During the 1990s Martin McGuinness was involved in secret exchanges of information with the British Government, via intermediaries.
By the 1997 general election, politics bore fruit for Sinn Fein when both Mr McGuinness and Gerry Adams were returned as MPs.
Characterised as a dispassionate strategist, Mr McGuinness became Sinn Fein's chief negotiator in the Good Friday Agreement talks. Along with Mr Adams, he remains the movement's main public face.
Following election to the new Northern Ireland Assembly, Sinn Fein nominated Mr McGuinness to become education minister.
That sparked fury from some unionists - though Mr McGuinness insisted that he would govern for all children.
When he brought his 1970s IRA role out of the shadows, some believed that it marked another shift by republicans away from violence and secrecy and into democratic peaceful debate.
Others have attacked it as motivated more by a determination to have the republican line accepted at the inquiry - the critics ask why senior republican colleagues such as Gerry Adams appear no more willing to talk about their past.
Mr McGuinness has a ready answer for this - one he used to cheering at a Sinn Fein rally in October 2002 when devolution collapsed amid allegations of IRA spying.
His critics, he said were afraid of change.
"They would love the IRA to go back to war. I'm delighted that we have not fallen into this trap.
"I'm delighted that we have an organisation which understands the political dynamics [of the peace process].
"There is a confidence and assertiveness among nationalists," he continued.
"We know who we are, we are Irish, we are proud of it."
Irrespective of what position he now holds within the movement, his republican credentials have remained as impeccable to this day.