"Today, we are in a great need of dialogue between civilisations, and peaceful coexistence... Today, we need to make the fight against terrorism an absolute priority," said Houcine Abassi, secretary general of the Tunisian General Labour Union (UGTT), one of the four members of the Quartet.
At Oslo's City Hall, which was decked out in flowers, Abassi denounced the "barbaric and heinous terrorist acts" in recent months in Tunisia and around the world, pointing to Paris, Beirut, Sharm el-Sheikh and Bamako.
The UGTT, the Human Rights League, the Confederation of Industry, Trade and Handicrafts (UTICA), and the Order of Lawyers orchestrated a lengthy and thorny "national dialogue" between the Islamists of the Ennahda party and their opponents.
"This year's prize is truly a prize for peace, awarded against a backdrop of unrest and war," said Kaci Kullmann Five, head of the Norwegian Nobel Committee.
One by one, representatives of the four organisations held aloft the Nobel diploma and gold medal to a standing ovation from the specially-invited guests, including Norway's King Harald and members of the Norwegian government.
In honouring the Quartet, the Nobel Committee shone the spotlight on Tunisia as a rare success story to emerge from the Arab Spring, which had its beginnings in the North African nation.
After hammering out compromises between groups initially diametrically opposed to each other, Tunisia successfully adopted a new constitution in January 2014 and held democratic elections at the end of last year.
At the same time, uprisings in neighbouring Libya, Yemen and Syria have led to war and chaos, and to the return of repression in Egypt.
Despite its successes, Tunisia's democratisation process remains fragile.
