Sir Josias Cunningham was the Ulster Unionist Party's "stabilising and guiding influence", according to the party's security spokesman, Mr Ken Maginnis. "He recognised that the nature of politics was changing and that the Ulster Unionist Party had to change with it," a visibly shaken Mr Maginnis said.
Born in Co Antrim on January 20th, 1934, Sir Josias was one of Ulster Unionism's most respected elder statesmen, a fact recognised when he was knighted in this year's New Year's Honours List for his services to politics.
President of both the Ulster Unionist Party and the party's 860-strong ruling council for the past 10 years, Sir Josias held the fate of the Belfast Agreement in his hands when, in November of last year, he was entrusted by the party leader, Mr David Trimble, with his post-dated letter of resignation to come into operation if IRA decommissioning did not occur by the end of January 2000.
It is widely believed that it was Sir Josias's presence, letter in hand, that forced the Northern Secretary, Mr Peter Mandelson, to suspend the North's power-sharing Assembly on February 11th.
Sir Josias was born into one of Belfast's wealthier merchant families. They had traded with the West Indies in the 18th century but shifted their main focus to stockbroking where they made their fortune. The family firm, Cunningham Coates, celebrated its 150th anniversary in 1993 before being taken over by the Ulster Bank.
One of the North's leading unionist families, Sir Josias's grandfather, Samuel, signed cheques to pay for 50,000 German rifles landed at Bangor and Larne in 1914 by Sir Edward Carson's Ulster Volunteer Force.
Sir Josias graduated in biological sciences from Cambridge University before joining the family firm. Last year he left to run the 300-acre family farm at Templepatrick, Co Antrim, and devote more time to his pastimes, theology and the study of poet Rudyard Kipling. A member of the Kipling Society, he was also an Orange Order deputy grand master and deputy lieutenant for Co Antrim.
The UUC president played an instrumental role in the BrookeMayhew peace talks in the early 1990s.
He was understood to be close to the former UUP leader, Lord Molyneaux, although at the time of Lord Molyneaux's resignation there was speculation that he had put some pressure on his leader to bow out, something always denied by Sir Josias.
Nevertheless, he was quoted as wondering at the time "whether a leader who lasts through a couple of decades is necessarily a good thing. It is probably a job which should not last so very long."
While his role as UUP president required him to adopt a neutral position and he was well respected by all in the party, it was understood that Sir Josias was quietly supportive of Mr Trimble and his pro-Belfast Agreement stance.
Earlier this year, Sir Josias indicated that he would "dearly like out of the job" as UUC president but was persuaded to stay on by the party's leadership to avoid "further bloodletting" within the UUP.
Once described as "the man with the grey sash", he was a steady hand who managed to stay above the party's internal divisions.
Sir Josias is survived by his wife, Anne, and four children, Miranda, Stephen, Penny and Jonathan.