Spain's Supreme Court has sentenced nine Catalan separatist leaders to between nine and 13 years in prison for sedition over their role in an independence referendum in 2017.
Three other defendants were found guilty of disobedience and fined, but will not serve prison sentences.
The 12 politicians and activists had all denied the charges.
In response to the verdicts, Catalan independence supporters marched in Barcelona before blocking some streets.
Some of those sentenced had held prominent positions in Catalonia's government and parliament, while others were influential activists and cultural advocates.
The 12 defendants pictured in the court in Madrid on the final day of their trial in June
During four months of hearings, they told the court in Madrid that they were victims of an injustice in a trial built on "false" charges.
The prosecution had sought up to 25 years in prison for Oriol Junqueras, the former vice-president of Catalonia and the highest-ranking pro-independence leader on trial.
Junqueras was handed the longest sentence of 13 years for sedition and misuse of public funds.
Others to receive prison sentences for sedition were:
The nine leaders, who had already spent months in pre-trial detention, were acquitted of a more serious charge of rebellion.
The remaining three defendants were earlier released on bail.
Monday's ruling comes after four months of hearings.
During their closing arguments in June, defence lawyers told the court their clients denied the charges of rebellion and sedition, but admitted to the lesser charge of disobedience, which could have seen them banned from public office but avoid prison.
Following the court's verdict, Catalan independence supporters marched in Barcelona, displaying banners that read "free political prisoners" and urging others to "take to the streets".Image copyright Getty Images
People took to the streets of Barcelona to protest against the court's decision
Carles Puigdemont, the former Catalan president who escaped trial after fleeing Spain before he could be arrested in 2017, said the sentences handed to separatist leaders of "100 years in total" were "an atrocity".
"Now more than ever... it is time to react like never before," he wrote on Twitter, adding: "For the future of our sons and daughters. For democracy. For Europe. For Catalonia."
The Catalan National Assembly called for "mobilisations around the globe" - including in the UK, France and Germany - in a tweet using the hashtag #StandUpForCatalonia.
Others used the hashtag to post footage of students marching in protest against the sentences moments after they were announced on Monday.
Meanwhile, both FC Barcelona and the Catalan football federation condemned the prison sentences and called for "dialogue and negotiation" to resolve the situation.
Over the weekend, hundreds of protesters rallied in the city.
Media captionCatalonia independence protesters: 'We feel like we are all being tried'
In 2017, police and protesters clashed in the streets when Catalonia's pro-independence leaders went ahead with the referendum, which had been ruled illegal by Spain's constitutional court.
Prosecutors argued that the unilateral declaration of independence was an attack on the Spanish state and accused some of those involved of a serious act of rebellion.
They also said that separatist leaders had misused public funds while organising the 2017 referendum.
Prosecutors argued the leaders had carried out a "perfectly planned strategy... to break the constitutional order and obtain the independence of Catalonia" illegally.
Forcadell, the former parliament speaker who read out the independence result on 27 October 2017, was also accused of allowing parliamentary debates on independence despite warnings from Spain's Constitutional Court.
Some of the leaders, speaking to the BBC ahead of the trial, said the proceedings were political in nature. Any violence, they said, was on the part of police and committed against voters in a crackdown which made headlines around the world.
Three weeks after the banned 2017 vote, the Catalan parliament declared an independent republic.
Madrid stepped in to impose its rule on the region, and several Catalan leaders fled or were arrested.
Catalan nationalists have long complained that their region, which has a distinct history dating back almost 1,000 years, sends too much money to poorer parts of Spain, as taxes are controlled by Madrid.
The wealthy region is home to about 7.5 million people, with their own language, parliament, flag and anthem.
In September, a march in Barcelona in support of Catalonia's independence from Spain drew crowds of about 600,000 people - one of the lowest turnouts in the eight-year history of the annual rally.