Ireland loses a 'great friend' following death of Dan Rooney
Irish America and the island of Ireland have lost a "great friend" following the death of Dan Rooney.
The former US ambassador to Ireland was 84.
President Michael D Higgins led the tributes to Mr Rooney, who was appointed to the role by Barack Obama in 2009, and who served until he resigned from the post in 2012.
He was sworn in by then Secretary of State, Hillary Clinton.
In a statement, President Higgins said Mr Rooney was "deeply committed to Ireland and the Irish people".
He added that thanks to his contributions through the Ireland Funds, "many projects promoting peace and reconciliation in Ireland were initiated".
Mr Rooney was born in Pittsburgh in 1932 into a family that helped to found the Steelers, one of American football's most successful sides.
He married another Pittsburgh native, Patricia Regan, known as Peggy, and they had nine children. He also funded the annual Rooney prize for Irish literature, which highlights the work of Irish writers aged under 40.
Taoiseach Enda Kenny expressed his sadness on learning of Mr Rooney's passing.
"Dan was a personal friend of mine and the proudest Irish supporter of the Pittsburgh Steelers.
"During his time as American ambassador to Ireland, Dan visited every county, and his work brought both the United States and Ireland closer together.
"He leaves a massive legacy which will benefit many people for the years to come. My deepest condolences go to his wife Patricia, and his entire family at this time," Mr Kenny added.
Described as a "proud" Irish-American, he co-founded the Ireland Funds with Sir Anthony O'Reilly in 1976.
This later merged with the American Irish Foundation to form the American Ireland Fund - and he served as vice chairman.
John Fitzpatrick, chairman of The Ireland Funds America, said Mr Rooney was "an utter gentleman and utterly selfless".
"The work of the Ireland Funds is his legacy and Ireland is a better place because of him. Thousands have benefited from his care and concern. He was a lion of a man and one of the most gentle and generous people one could ever meet," said Kieran McLoughlin, worldwide president and CEO of The Ireland Funds.
"Together with his co-founder Tony O'Reilly, Dan was the soul and sage of this organisation. He did so much, for so many, so willingly."
Sinn Fein president Gerry Adams extended his "sincerest sympathies to Ambassador Rooney's wife Peggy and family".
He added: "I met Dan and his wife Peggy in Pittsburgh some years ago. They were both interested in and supportive of the peace process. Their philanthropy and kindness is legendary in Pittsburgh and beyond. As ambassador he initiated a series of gatherings to discuss how best to develop cross-border projects."
Mr Rooney was awarded an honorary CBE in 2008 for his contributions to peace and reconciliation. SDLP leader Colum Eastwood hailed him as "a great friend of Ireland".
The US Embassy said the former ambassador was "loved by all who met him, including everyone who worked with him at the US Embassy in Dublin".
President Obama described Mr Rooney as a "great friend... who represented the United States with dignity and grace on the world stage".
Mr Rooney was well-known in American football circles as owner and chairman of the Pittsburgh Steelers NFL team.
He first became involved with the Steelers in 1955, later succeeding his father to become president in 1975. His son, Art, took over in 2003 and his father became the club's chairman. He was inducted into the Professional Football Hall of Fame in 2000.
The Pittsburgh Steelers said: "Dan Rooney touched so many lives, from the men who played for him, to presidents and world leaders."