SDLP leader John Hume spent his entire political career working to try to remove Northern Ireland from the United Kingdom and turn it into a united Ireland.
But he is best known for his efforts to secure peace and a power-sharing government in Northern Ireland which culminated in the Good Friday Agreement in 1998.
Unionists unfairly accused him of riding on the back of the IRA campaign of violence.
But he was unstinting in his opposition to the use of terrorism for any means and made several brave attempts to convince the republican movement that the campaign of violence should be ended.
In 1985 he briefly met directly with the IRA to try to win a ceasefire, but failed and incurred the wrath of the Irish government.
Three years later he engaged in unsuccessful talks with Gerry Adams, then president of the IRA’s political wing, Sinn Fein, to try to gain not a ceasefire, but a permanent end to violence.
In 1993 he again met Mr Adams several times and they drew up proposals which were passed to the Irish government saying they could form the basis for a lasting peace in Ireland.
In 1997 his efforts were finally rewarded when in July the IRA announced the renewal of its 1994 ceasefire.
Political talks ensued which eventually led to the signing of the Good Friday Agreement in 1998.
Unionist politicians viewed Mr Hume as just as dangerous to their cause as the IRA.
Educated and eloquent, he enunciated the case of constitutional nationalism.
Mr Hume articulated the feelings of the ever-growing Catholic middle-class and early on constructed a theory which changed little over the years – that the heart of the Irish question lay not with the British but with the Ulster Protestants and that partition was not the cause of division but a symptom of it.
A solution to the age-old problem could only be found with agreement from the Protestants.
Their numbers gave them a veto and they could not be forced into any new arrangement against their will, he argued.
Born in Londonderry in January 1937, the oldest of six children, Mr Hume came from the first generation to benefit from the 1944 Education Act and went to the local grammar school, St Columb’s College.
He went on to Maynooth College, the Catholic seminary near Dublin, to study French and modern history before returning to teach in his old school.
In 1960 he married his wife Pat, had five children and continued to live in the republican Bogside area of Derry despite regular attacks on his home.
His involvement in the 1960s with the Credit Union movement brought him into contact with the issues of the day, housing and anti-Catholic discrimination in a city where Protestants were in the minority but boundary gerrymandering gave them a Unionist majority on the local council.
He first came to political prominence in the civil rights movement in 1968.
He was present at the civil rights march in October that year which ended in disorder and set the spark to decades of violence.
But his reputation for non-violence was established on the streets at a time others sought revolution and confrontation.
Ironically, during his brief excursion into street politics, he was pulled in and questioned, as a non-violent demonstrator, by an enthusiastic Marines captain called Paddy Ashdown.
The following year he was returned to the old Stormont parliament as MP for Foyle, unseating the then Nationalist leader Eddy McAteer.
In 1970 he was one of the founding fathers of the Social Democratic and Labour Party (SDLP) and soon emerged as its chief policymaker.
He became leader in 1979.
He was elected to the 1973-74 Northern Ireland Assembly and was head of the Department of Commerce in the ill-fated power-sharing executive in 1974. He was also elected to the 1982-86 Northern Ireland Convention.
He was elected as one of Northern Ireland’s three MEPs in 1979 and made it to Westminster in 1983 when boundary changes created the new Foyle seat, the first time a non-Unionist had got a seat in parliament for Londonderry since the establishment of Northern Ireland.
He was seen as the main architect of the Anglo-Irish Agreement signed between the British and Irish Governments in 1985 and which, much to Unionist fury, gave Dublin a say in the affairs of Northern Ireland.
Mr Hume led his party in various talks with the British Government and other local parties during efforts to set up a devolved administration.
Following extensive and often heated discussions, the Good Friday Agreement was signed on April 10 1998.
Devolved government followed with a local Assembly sitting at Stormont led by Ulster Unionist leader David Trimble.
Many had expected Mr Hume to become deputy first minister as the leader of the then second largest party.
But instead Seamus Mallon took on that role, amid rumours of a bad working relationship between Mr Hume and Mr Trimble.
In 1998, Mr Hume won the Nobel Peace Prize, jointly with Mr Trimble.
He built up a reputation as an international politician, winning the ear of the Irish government, European leaders and, possibly most important of all, the powerful Irish-American lobby.
Within Europe he spearheaded economic initiatives which won Northern Ireland special financial aid, and fellow MEP and arch political foe, the Rev Ian Paisley, lined up in support.
He was also a recipient of the Gandhi Peace Prize and the Martin Luther King Award.
In the summer of 1999, Mr Hume was taken ill at a conference in Austria, and had to undergo a series of operations.
He retired as leader of the SDLP in 2001, succeeded by fellow Derry man Mark Durkan.
He announced his retirement from politics in 2004.
His Foyle Westminster seat was successfully defended in 2005 by Mr Durkan.
However Mr Hume’s party and the UUP suffered electorally since the signing of the Good Friday Agreement, overtaken by Sinn Fein and the DUP.
It was a sad moment for the SDLP in June 2017 when Mr Hume’s former seat in Foyle was lost to Sinn Fein.
The party also lost South Down and South Belfast, leaving them without any MPs.
That election temporarily signalled the end of Irish nationalism having a voice at Westminster, given Sinn Fein does not take its seats.
In last December’s election, the SDLP returned to the green benches of the Commons, when current leader Colum Eastwood regained the Foyle seat in a landslide win and party colleague Claire Hanna won back South Belfast.
Mr Hume’s impact on politics has been recognised a number of times.
In 2010 he was named Ireland’s Greatest in a public poll by Irish national broadcaster RTE.
In 2012, Pope Benedict XVI made him a Knight Commander of the Papal Order of St Gregory the Great.
Mr Hume, who was 83 in January, had been suffering from dementia for many years.
In May 2018, he was too ill to attend a ceremony at Queen’s University in Belfast to mark the 20th anniversary of the signing of the Good Friday Agreement.