A book of condolence has opened at Belfast City Hall for Seamus Mallon who died aged 83.
The former SDLP deputy leader was an architect of the Northern Ireland peace process and a key figure in negotiating the 1998 Good Friday Agreement.
It is understood Mr Mallon had been suffering from an illness for some time.
Hollywood actress Sharon stone signed the book, "With respect and admiration"
The leader of the SDLP in Belfast Councillor Dónal Lyons described Mr Mallon as "a stand out figure of his political generation who came to define the peace process".
He added, "Seamus was his own man and I admire him for that. He knew his own mind and he brought a steady insight and wisdom to any problem. He didn't think in days and weeks, he thought in years and generations."
Tributes have been pouring in from across the political world.
Bill Clinton, who was in office at the time of the Good Friday Agreement and championed peace talks in the 1990s, paid his own tribute to Mr Mallon
"From his earliest entry into politics, Seamus never wavered from hisvision for a shared future where neighbours of all faiths could live indignity-or from the belief he shared with John Hume and the entire SDLP that nonviolence was the only way to reach that goal"
Former Prime Minister Tony Blair said he was one of the most important architects of non-violence.
"Brave, blunt, often prepared to swim against the tide if he felt it right, hewas someone deeply respected and admired across the troubled landscape of Irish politics".