Key dates in community's push for independence

'We are a nation'

March 2006: Catalans agree a new autonomy charter, increasing their fiscal and judicial powers and describing Catalonia as a "nation".

June 2010: Spain's Constitutional Court strikes down parts of the charter, in response to an appeal filed by Rajoy's conservative Popular Party (PP).

A month later, hundreds of thousands of people protest in Barcelona against the ruling, amid chants of "We are a nation, we decide".

Demands for independence

September 11, 2012: More than a million people protest in Barcelona demanding independence for Catalonia. Major demonstrations are held in the following years on the same date, marking Catalonia's national day.

September 20: Prime Minister Mariano Rajoy rejects Mas's call for greater tax-and-spend powers for the region. Mas then calls a snap regional election promising to hold a referendum on Catalonia's future.

November 26: Mas's centre-right CiU alliance wins the election overall but fails to secure an absolute majority in the regional parliament.

Human chain

September 11, 2013: Hundreds of thousands of Catalans form a human chain stretching more than 400 kilometres (250 miles) across the Mediterranean coast to push for independence.

Symbolic vote

November 9, 2014: Catalonia defies Madrid and presses ahead with a symbolic vote on independence. Turnout is just 37 percent, of which over 80 percent vote in favour of independence.

Parliamentary majority

September 27, 2015: The pro-independence Together For Yes alliance secures 62 seats in the regional assembly and the radical leftwing separatist group CUP wins 10, giving them an absolute majority.

But the separatist block falls short of winning a majority, which is portrayed as a plebiscite on independence, capturing just 47.8 percent of the ballot.

November 9: All 72 pro-independence lawmakers in the Catalan parliament vote to kick off the process to secede from Spain. The country's Constitutional Court will later strike it down.

January 10, 2016: Carles Puigdemont becomes president of Catalonia.

Referendum day

March 2017: Catalan ex-president Artur Mas is found guilty of "disobedience" for staging the 2014 symbolic referendum. He is banned from holding public office for two years.

June: Puigdemont announces a referendum to be held on October 1. Voters are asked: "Do you want Catalonia to be an independent country in the form of a republic?" Spain's central government vows to block the vote.

October 1: The regional government defies a ban and presses ahead with its referendum. A major police crackdown sends shock waves around the world.

Turnout is around 43 percent, of which 90 percent back independence.

October 27: The Catalan parliament defies multiple warnings from the central government and unilaterally declares independence from Spain.

Madrid takes the unprecedented step of stripping the region of its autonomy, sacking its government and parliament.

Separatists behind bars, in exile

November 2017: Puigdemont goes to Belgium, before a Spanish court charges him and other top members of the axed government with sedition and rebellion.

His former deputy Oriol Junqueras and other secessionists are remanded in custody pending trial.

December 19: Separatists and pro-unity candidates hold their final campaign rallies, with deposed ex-leader Puigdemont speaking to supporters via videolink from exile.

December 21: Catalonia begins voting in the snap regional election called by Madrid.

It is unclear what will happen should Puigdemont or Junqueras, who is behind bars, win on Thursday.