The European Union has accepted the Nobel Peace Prize at a ceremony in Oslo's City Hall, despite criticism from past winners that the bloc is based on "military power".
A number of Europena leaders were in attendance, including Angela Merkel, the German chancellor, and Francois Hollande, the French president, who were seated beside each other.
The prize was received jointly by European Council President Herman Van Rompuy, European Parliament President Martin Schulz and European Commission President Jose Manuel Barroso.
The prize was awarded for the stability and democracy brought to the continent more than five decades after two world wars.
Archbishop Desmond Tutu, who won the prize in 1984 for his campaign against South African apartheid, said it was wrong to recognise the EU as it was an organisation based on "military force".
Tutu was joined by past winners Mairead Maguire of Northern Ireland and Adolfo Perez Esquivel from Argentina in their opposition to the EU receiving the award.
Arguing the bloc contradicts the values associated with the prize because it relies on military force to ensure security, they demanded that the prize money of $1.2m not be paid this year.
Others have criticised the decision because the bloc is mired in economic and financial crisis.
Van Rompuy, president of the council that represents EU leaders, invoked his own family history to highlight how raw the memories of World War Two remain.
"As a child born in Belgium just after the war, I heard the stories first hand," he said in his acceptance speech.
"In 1940, my father, then 17, had to dig his own grave. He got away; otherwise I would not be here today.
"So what a bold bet it was for Europe's founders to say, yes, we can break this endless cycle of violence, we can stop
the logic of vengeance, we can build a brighter future."
On Sunday about 1,000 members of activist and human-rights groups marched through the Norwegian capital in protest, saying the EU was not a rightful beneficiary under the terms Alfred Nobel laid down in his 1895 will.
"Alfred Nobel said that the prize should be given to those who worked for disarmament," said Elsa-Britt Enger, 70, a
representative of Grandmothers for Peace.
"The EU doesn't do that. It is one of the biggest weapons producers in the world."
The Nobel prize money will be given to projects that help children struggling in war zones, with the recipients to be announced next week.
The EU has said it will match the prize money, so that a total of two million euros will be given to the selected aid projects