Tunisia's National Dialogue Quartet has won the Nobel Peace Prize for building democracy after the 2011 revolution which unleashed the Arab Spring.

Four years later, Tunisia is the only country caught up in the Arab Spring uprisings where widespread protests have paved the way for a nascent democratic transition.

The quartet has been instrumental in this process. Here are five things about the grouping:

1. Who are they?

The Tunisian quartet is made up of four respected organisations in the North African nation: the Tunisian General Labour Union, the Tunisian Confederation of Industry, Trade and Handicrafts, the Tunisian Human Rights League, and the Tunisian Order of Lawyers.

2. Why these four organisations?

The Tunisian General Labour Union is the most crucial party of the four, and a hugely influential institution which 5 per cent of the Tunisian population counts as members.

The quartet's economic clout was enhanced by the Tunisian Confederation of Industry, Trade and Handicrafts, which represents employers and generally stands opposed to the Labour Union.

The Tunisian Human Rights League is the first independent human rights association in the Arab world, while the Tunisian Order of Lawyers also helped pilot the fight for Tunisia's independence.

3. Why did they come together?

In 2013, Tunisia appeared to be sliding into a political crisis that threatened to end its democratic transition, with secular opponents demanding that an Islamist-led government step down.

Tunisia's opposition was angered by the assassinations of two of its leaders and held protests against the ruling Islamist Ennahda party.

The quartet negotiated between the two sides, helping form a caretaker government to hold power until new elections were held.

4. What has Tunisia accomplished?

Tunisia now has a new constitution, free elections and a coalition government with secular and Islamist parties.

In December 2014, Tunisians voted in the first free presidential election held in the country since independence from France in 1956.

But this year it was hit by a massacre at a Tunis museum in March that killed 22 people, mostly tourists, and a mass killing at a beach resort last month that left 38 foreigners dead.

5. Why were they awarded the Nobel Peace Prize?

The Nobel Committee said on Friday (Oct 9) the award was given for the quartet's "decisive contribution to the building of a pluralistic democracy in Tunisia in the wake of the Jasmine Revolution of 2011". The committee said the prize was also intended as an encouragement to other countries to follow in Tunisia's footsteps.

Sources: AFP, REUTERS, CARNEGIE ENDOWMENT FOR INTERNATIONAL PEACE