David Ervine supported a modern form of non-sectarian unionism "free from the Pope, the Queen and King Billy".
David Ervine became Progressive Unionist leader in 2002
A former UVF prisoner who became a party leader, he was without question a key figure in the transformation of loyalism.
He encouraged his community to separate politics from religion, and although he was a staunch supporter of the Union, he became well-known for a willingness to compromise and to at least listen to republican and nationalist concerns.
Born in east Belfast in 1953, he left school at 15 with few qualifications.
As the Troubles intensified at the end of the 1960s, he became involved with hardline loyalism and joined the UVF.
He said: "It was the increase in bombings and people being found dead up entries. You almost felt you had to get involved, especially with the arrival of a young son. I was thinking 'I've got to defend this'."
When he was in his early 20s, Mr Ervine was jailed after he was caught by the security forces in a car which contained a bomb in 1974.
While he was inside, he was encouraged by UVF leader Gusty Spence to become more politically aware.
David Ervine served five years in the Maze prison
Upon his release in 1980, Mr Ervine joined the Progressive Unionist Party, which was established to give political voice to the UVF.
However, he remained candid about his past involvement in paramilitarism.
When he was asked in a 1999 BBC documentary if he had been prepared to kill, he replied: "Without question, totally. (It was) my decision and made by me and me alone."
He helped broker the loyalist ceasefire of October 1994 and was elected to represent East Belfast first on Belfast City Council and then at the Stormont Assembly.
Mr Ervine was a prominent supporter of the 1998 Good Friday Agreement, both in the run up to its drafting and as a campaigner for a 'Yes' vote in the referendum, working hard to keep onside a wary loyalist community.
And he won credit for trying to wean loyalists away from violence.
David Ervine pictured in 1998, the year of the Agreement
But he also attracted criticism over continued feuding between the UVF and paramilitary rivals the LVF, and the failure of loyalists to decommission their weapons.
Last year, he was at the centre of a row over a planned Assembly alliance between his party and the Ulster Unionists.
Eventually the arrangement was ruled out of order.
David Ervine was one of loyalism's most articulate voices and through his frequent appearances on the media, one of its best-known voices.
His death will undoubtedly leave a void in loyalist politics.