Widespread tributes to US philanthropist Chuck Feeney, who was lauded by nationalists but who sometimes caused concern among unionists

In times past, however, his influence has raised concerns among some unionists, most recently when his money was discovered to have been behind a Belfast High Court challenge to Brexit in 2016.

The celebrated philanthropist traced his family roots to County Fermanagh, close to Kinawley and the townland of Larganacarran.

Born in 1931 in New Jersey at the height of the Great Depression, he graduated from Cornell University, after receiving a US military scholarship.

He co-founded the Duty Free Shoppers group in 1960 and amassed a personal fortune. He later founded Atlantic Philanthropies, which gave almost $9bn to various worthy causes around the world.

It is believed that he donated up to $1.3bn on projects in the Republic while $570m went to causes in Northern Ireland, including integrated education.

Atlantic Philanthropies says that his interest in NI began with deaths caused by the Enniskillen bomb in 1987.

In 1993 he and other Irish Americans met Gerry Adams, and within a year he funded a Sinn Féin office in Washington "to promote political alternatives". In 2007 he "participated" in the launch of the Stormont power-sharing government.

In 2015 the Irish Times reported that Mr Feeney was the largest funder of Sinn Fein in the US from 1995 to 2014, donating £512,000. There have been unconfirmed reports he also donated money to the UDA to bring it into the peace process.

Ms O’Neill said: “Chuck Feeney will be remembered fondly across Ireland as a man who made a generous and very important contribution to the development of the peace process.

“He will also be remembered for his financial philanthropy in the areas of health, education, research and community grassroots peace-building and rights activism."

SDLP leader Colum Eastwood MP said: “Chuck Feeney used his wealth to help others and it’s a testament to his work that many of his contemporaries have followed his example."

The vice-chancellor of Queen’s University Belfast, Professor Sir Ian Greer, said he was "an outstanding advocate and supporter of the higher education sector on the island of Ireland".

In 2016 the News Letter revealed that a High Court challenge to Brexit fronted by Sinn Fein, the SDLP, Alliance and Greens was actually being funded with money which came from Mr Feeney. Although the money came from him, it was not clear whether he personally supported the case.

TUV leader Jim Allister said in the aftermath that the news "also raises the question of what else has been funded by this outfit".

It is understood that Atlantic Philanthropies gave £673,000 to the NI Human Rights Consortium in 2006. UUP peer Lord Laird said at the time that Mr Feeney’s continuing involvement was fuelling unionist concerns that the Bill of Rights was a "shopping list for Sinn Fein".

The Evangelical Alliance expressed concern that the Bill of Rights could cause community division and was promoting rights without any corresponding responsibilities. CARE said it would make abortion easier, while doing nothing to protect unborn children.