US President Barack Obama has praised Edward Kennedy as a 'singular figure' in US history, hours after the Massachusetts Senator died aged 77.
Ted Kennedy, the 'liberal lion' of the US Senate, who was once tipped to succeed his assassinated brother John as president, died late last night at his home in Hyannis Port, Massachusetts.
'Even though we knew this day was coming for some time now, we awaited it with no small amount of dread,' Mr Obama said in a brief statement at Martha's Vineyard.
'His fight has given us the opportunity we were denied when his brothers John and Robert were taken from us: the blessing of time to say thank you and goodbye.'
Edward Kennedy died just two weeks after his sister Eunice Kennedy Shriver passed away at the age of 88. Gravely ill, Ted Kennedy was unable to attend the funeral in Cape Cod.
The youngest of the Kennedy sons, Edward was left to take up the helm of the political dynasty after the assassinations of president John Kennedy in Dallas 1963 and of Robert Kennedy while on the presidential campaign trail in June 1968.
Listen to Edward Kennedy's eulogy at Robert Kennedy's funeral in New York on 8 June 1968
View images from Edward Kennedy's life and career
Ted was the only Kennedy son not to die in a violent incident. Joe Kennedy, a pilot, died while on a World War II bombing mission.
When he first took the Senate seat previously held by John Kennedy in 1962, he was seen as something of a political lightweight who owed his ascent to his famous name.
Yet during his nearly half century in the chamber, Mr Kennedy became known as one of Washington's most effective senators, crafting legislation by working with lawmakers and presidents of both parties, and finding unlikely allies.
At the same time, he held fast to liberal causes deemed anachronistic by the centrist 'New Democrats', and was a lightning rod for conservative ire.
He helped enact measures to protect civil and labour rights, expand healthcare, upgrade schools, increase student aid and contain the spread of nuclear weapons.
The senator also played a significant role in establishing peace in Northern Ireland, helping to smooth the negotiations which led to the 1998 Good Friday Agreement.
'There's a lot to do,' Mr Kennedy told Reuters in 2006. 'I think most of all it's the injustice that I continue to see and the opportunity to have some impact on it.'
Chappaquiddick
But he never fulfilled what many had seen as his political destiny, his White House hopes dashed after his name was tainted by scandal and drinking problems.
In 1969, Ted Kennedy drove off a bridge at Chappaquiddick in Massachusetts, killing female companion Mary Jo Kopechne and leaving the scene of the accident.
His image took a major hit after it emerged he had failed to report the accident to authorities. He pleaded guilty to leaving the scene and received a suspended sentence.
He eventually ran for his party's presidential nomination in 1980 but lost to then-President Jimmy Carter.
His presidential ambitions thwarted, Ted Kennedy devoted himself to his Senate career.
'Edward M Kennedy - the husband, father, grandfather, brother and uncle we loved so deeply - died late Tuesday night at home in Hyannis Port, Massachusetts,' the Kennedy family said in a statement.
'We've lost the irreplaceable centre of our family and joyous light in our lives, but the inspiration of his faith, optimism, and perseverance will live on in our hearts forever', the statement read.
A US official has said the body of the late Senator Ted Kennedy will lie in state on Friday and his funeral will take place on Saturday.
US media are saying the late senator will be buried at Arlington National Cemetery, where his assassinated brothers, John and Robert, are buried.
'A great friend of Ireland'
President Mary McAleese has said Senator Kennedy's death will be greeted in Ireland with a great sense of sadness because of his long-standing affection for this country and his role - not just in the peace process but also in other issues, including immigration.
Taoiseach Brian Cowen also offered his condolences to the Kennedy family.
In a statement, Mr Cowen said: 'Ted Kennedy has been a great friend of Ireland. He has used his considerable influence in the world's most powerful parliament for the betterment of this island.
'In good days and bad, Ted Kennedy worked valiantly for the cause of peace on this island. He played a particularly important role in the formative days of the Northern Ireland Peace Process in the early to mid-1990s. He has also always been a strong advocate of US investment in Ireland.
'Today, America has lost a great and respected statesman and Ireland has lost a long-standing and true friend.'
Former Taoisigh have also paid tribute.
Bertie Ahern said Ireland had lost a very good friend. He said he was one of a small group of important American politicians who had taken a keen interest in Irish affairs, since the start of the Troubles in Northern Ireland to present times.
Garrett Fitzgerald said Senator Kennedy was an extraordinary man, who was a great legislator. He said the Senator helped block the influence of the IRA in the US.
US Ambassador to Ireland Dan Rooney said: 'Senator Kennedy was not only a great American Statesmen, but also a great friend of mine and all the island of Ireland and its people.'
In London, British Prime Minister Gordon Brown stated that Mr Kennedy would be 'mourned not just in America but in every continent'.
Northern Ireland Deputy First Minister Martin McGuinness praised the late Mr Kennedy for his enormous contribution to the peace process.
The late Senator was also being remembered in Co Wexford today, especially in his ancestral home of Dunganstown near New Ross.
The Senator visited the area a number of times in the past and kept in close contact with family members there.
A book of condolence will open tomorrow morning for two days at the US Embassy in Ballsbridge, Dublin, from 9am to 12pm and 1pm to 5pm.
