- Video obituary by ITV News Correspondent Dan Rivers
Once described as "Britain's number one terrorist", the key Northern Ireland peace figure Martin McGuinness - who has died at 66 - always acknowledged his IRA past.
At 21 he was second-in-command of the IRA in Derry when 14 civil rights protesters were killed by British soldiers in the city on Bloody Sunday.
The following year the former butcher's assistant was convicted by the Republic of Ireland's Special Criminal Court and jailed after being arrested near a car containing explosives and ammunition.
After another conviction in the Republic for IRA membership, he became increasingly prominent in Sinn Fein alongside Gerry Adams.
In 1982, Mr McGuinness was elected to the Northern Ireland Assembly at Stormont representing his home city of Derry, becoming the second candidate elected after John Hume.
But Mr McGuinness remained a key figure in the IRA throughout the 1980s as the Republican extremists pursued a deadly bombing campaign, which included the 1984 attempt to kill Prime Minister Margaret Thatcher in Brighton.
He was also accused of prior knowledge or involvement in several targeted bombings, though he denied the allegations.
Mr McGuinness, who had been part of an IRA delegation that held talks with the UK government after Bloody Sunday, remained in indirect contact with British intelligence during the hunger strikes in the early 1980s, and again in the early 1990s.
Mr McGuinness became increasingly receptive to a political solution to the Troubles.
He believed the conclusions of academics that the British Army could not militarily beat the IRA, but also claimed to believe the IRA could not defeat the British.
Mr McGuinness became motivated to convince people change could only happen through politics.
He eventually became Sinn Fein's chief negotiator in the talks that led to the Good Friday Agreement which ended violence, secured IRA arms decommissioning in 2005 and shared government with former enemies.
He would go on to become an undoubted establishment figure as Deputy First Minister (DFM) at Stormont, forging a close working relationship under staunch protestant Ian Paisley.
His bid to become Irish head of state in the 2011 presidential election ended in defeat before he stood down as the MP for mid-Ulster a year later.
The same year saw his historic handshake with the Queen.
They shook hands at a Belfast theatre and Mr McGuinness said the encounter was "a result of decades of work constructing the Irish peace process".
In 2014 he attended a banquet at Windsor Castle as part of a state visit by the Irish president and joined in a toast to the monarch.
Mr McGuinness went on to declare that he "genuinely regretted" every life lost during the Troubles.
In a speech at Westminster he said: "Every single violent act was evidence of a failure of politics and a failure of British policy in Ireland.
"I genuinely regret every single life that was lost during that conflict and today I want every family who lost a loved one to know that your pain is not being ignored and I am willing to work with others to finding a way to deal with our past so that we can complete our journey to true reconciliation."
Mr McGuiness' political career ended in January when he surprisingly quit his post as deputy first minister in protest over a failed energy scheme, triggering an election.
But his ill health was evident as he arrived at Stormont to deliver his resignation, explaining that he was no longer "physically able" to challenge for power.