Here is a timeline of the key events in Martin McGuinness's life and political career:
May 23 1950 - Born in Derry, one of seven children. He grew up in the Bogside area of the city and became a butcher. After being drawn to the civil rights movement Mr McGuinness joined the IRA.
January 30 1972 - At just 21, Mr McGuinness was the IRA's second-in-command at the time of the Bloody Sunday shootings, when 13 unarmed civil rights protesters were killed by British soldiers in Derry, another dying four days later.
1973 - Mr McGuinness was convicted by the Republic of Ireland's Special Criminal Court after being arrested near a car containing explosives and ammunition.
1974 - Claimed he had left the IRA, spending more time in politics. He became increasingly prominent in Sinn Fein, eventually becoming its best-known face after Gerry Adams.
1997 - Became the MP for Mid Ulster.
April 10 1998 - Mr McGuinness was Sinn Féin's chief negotiator in the talks that led to the Good Friday Agreement, ending years of violence. Following its agreement he was nominated by his party for a ministerial position in the power-sharing executive, where he became minister of education.
2005 - Helped secure IRA arms decommissioning.
2006 - Led negotiations during talks that paved the way for the St Andrew's Agreement.
May 2007 - Mr McGuinness became deputy first minister of Northern Ireland, with former Democratic Unionist Party leader Ian Paisley elected first minister.
October 2011 - Contested the Irish presidential election, coming third behind Michael Higgins and Sean Gallagher.
June 27 2012 - In a historic moment, Mr McGuinness shook hands with Queen Elizabeth at the Lyric Theatre in Belfast.
January 9 2017 - Mr McGuinness resigned as deputy first minister in protest at the handling of a botched energy scheme, forcing a snap election.