Bill Clinton has joined thousands of mourners for former IRA leader Martin McGuinness at a service in Derry.
Mr McGuinness. 66, died on Monday from a rare genetic condition.
Thousands of people lined the streets to watch his remains being carried to the church.
Mourners applauded as the former US President arrived at the requiem mass in Mr McGuinness's home city of Derry, Northern Ireland.
Theresa May did not attend, but the British Government was represented by Northern Ireland secretary James Brokenshire.
The service, in the Long Tower church, was also attended by ex-Democratic Unionist Stormont first ministers Peter Robinson and Arlene Foster.
Irish President Michael D Higgins and his predecessor, Mary McAleese, were also attending the funeral, as was Taoiseach Enda Kenny.
There was a round of applause inside the church as Mrs Foster took her seat.
The symbolism of the leader of unionism attending a former IRA man's funeral is highly significant - even more so in Mrs Foster's case, as her father survived an IRA murder bid during the Troubles and she herself was on a school bus caught up in an IRA bombing as a child.
Chief celebrant Father Michael Canny began his homily by asking mourners to join him in sharing thoughts and prayers with the people of London following Wednesday's terror attack.
He recalled the many tributes made to the Sinn Fein politician since his death and said it has been acknowledged that Mr McGuinness spent year after year moving the community towards peace.
"There are people in this church today whose presence would have been unthinkable only a generation ago," Fr Canny told mourners.
The congregation heard that the presence of Mr McGuinness's political rivals and opponents at the mass is "the most eloquent testimony" to his memory.
"When you seek his monument, look around you, you, by your presence are his monument," Fr Canny said.
But, he admitted, some still struggled to see past Mr McGuinness's IRA past.
"Republicans were not blameless, and many people right across the community find it difficult to forgive and impossible to forget," he said.
"By any standards, Martin McGuinness was a remarkable man and his life was a remarkable journey. The values he had, the principles he championed are still very much alive."
Other ministers paid tribute to Mr McGuinness. Local Presbyterian priest Rev David Latimer described him as a friend and spoke about praying with him.
"Martin had a good heart but I would go a bit further to say, he had a big heart that enabled him to reach out in quite unexpected ways to both to friends and to foes alike," he said.
"Martin has bequeathed to us a better place to live.
"It was his commitment to create a new order of co-operation where we will be able to live in relationship and not out of relationship and get to know each other better.
"In memory of the man whose friendship I will always treasure we must together, all of us, pledge to keep on doing what he was doing and to persevere in the pursuit of peace."
Earlier Mr McGuinness's beloved Bogside neighbourhood came to a standstill as his remains were walked to the church.
His wife Bernie carried the coffin as it made its way along part of the route the civil rights march took on Bloody Sunday in 1972.
The procession then made its way past the iconic Free Derry Wall mural.
Mr McGuinness completed an extraordinary political journey from an IRA leader in Derry to sharing power and a remarkable friendship with his erstwhile foe, DUP leader Dr Ian Paisley.
While he was leader of the IRA it carried out attacks including a remote controlled IRA bomb near Sligo which killed Lord Louis Mountbatten. Hours later, 18 paratroopers from the British Army were killed in an IRA ambush in Co Down.
But he also helped broker a historic peace deal, the Good Friday Agreement, in 1998.