Bono has warmly praised Garret FitzGerald's political handling of former British Prime Minister Margaret Thatcher.
The U2 singer, who struck up a friendship with the late Fine Gael leader during the early 1980s, claimed Dr FitzGerald's "biggest achievement" was signing the Anglo-Irish Agreement.
But Bono said this was possible only because of the effect he had on Mrs Thatcher, who Dr FitzGerald believed "really didn't think that much of the Irish".
"Garret told me many stories about dealing with Margaret Thatcher," the singer said.
"By the end of the peace process, he really admired her.
"He got to know all the cultural signifiers that had her in the place where she really didn't think that much of the Irish.
"I think that's true, coming from where she came from, from Lincolnshire, Irish people were on the lowest rung around there."
But the poverty campaigner said the then-Taoiseach had a "clever way of dismantling a political opponent" like Mrs Thatcher, which he did by "slowly and surely, getting to know the subject better than anybody".
"She (Thatcher) was a genuine unionist and a genuine patriot," Bono told Sam Smyth's Today FM programme. "By the end of her time with Garret, she's been accused, not of being a great patriot, but a great traitor.
"He (FitzGerald) had somehow re-organised Irish relations with Britain in a fundamental way, and the unionists had lost that card they could always play, which was the card of the British prime minister. Things would never be the same again."
Bono went on to recall how he and his wife Ali would go for dinner at the FitzGerald home, and "eat among the books" in the basement. Bono said it was "turned into a library" like everywhere else in the house.