Spain's Supreme Court has convicted 12 former Catalan politicians and activists for their roles in the secession movement of 2017.
The court sentenced former regional vice president Oriol Junqueras to 13 years for sedition and misuse of public funds.
The 12 were tried for their actions in a 2017 attempt by Catalonia to break away from Spain following an illegal independence referendum.
Grassroots pro-secession groups have previously said that if any of the defendants were found guilty they would organise protests and "peaceful civil disobedience".
Eight received lengthy prison terms in Catalonia's attempt to break away from Spain following an illegal independence referendum, while three received lesser sentences.
Although prosecutors had requested convictions for the more severe crime of rebellion, which under Spanish law implies the use of violence to subvert the constitutional order, judges convicted nine of sedition, implying that they promoted public disorder to subvert the law.
Spanish authorities have deployed hundreds of extra police to the region in anticipation of the ruling.
Reacting to the news on Twitter, Scotland First Minister Nicola Sturgeon said the result was a "dreadful outcome."
On Twitter Ms Sturgeon wrote: "These politicians have been jailed for seeking to allow the people of Catalonia to peacefully choose their own future.
"Any political system that leads to such a dreadful outcome needs urgent change. My thoughts and solidarity are with all of them and their families."
Regional parliament speaker Carme Forcadell was given 11-and-a-half years in prison; former cabinet members Joaquim Forn and Josep Rull 10-and-a-half years each; and grassroots pro-independence activists Jordi Sanchez and Jordi Cuixart nine years.
Junqueras and three other former cabinet members - Raul Romeva, Jordi Turull and Dolors Bassa, who were sentenced to 12 years - were also convicted for misuse of public funds.
Three other former members of the Catalan Cabinet - Santiago Vila, Meritxell Borras y Carles Mundo - were fined for disobedience.
The court's decision was another milestone in the long struggle for separatists who want Catalonia to break away from Spain and create a new European state. Spain insists it will not allow it. The Spanish constitution says the country is "indivisible".
The 2017 vote
The separatist effort fell flat when it won no international recognition. The Spanish government stepped in and fired the Catalan regional government, with prosecutors later bringing charges.
At the centre of the prosecutors' case was the October 1 2017 referendum that the Catalan government held even though the country's highest court had disallowed it.
The "Yes" vote won, but because it was an illegal ballot most voters did not turn out and the vote count was considered of dubious value. The Catalan Parliament, however, unilaterally declared independence three weeks later, triggering Spain's worst political crisis in decades.
Seven separatist leaders allegedly involved in the events, including ousted Catalan president Carles Puigdemont, fled the country and are regarded by Spain as fugitives.
Puigdemont tweeted on Monday: "A total of 100 year of prison. How horrible. Now more than ever, we will be with you and your families. For the future of our sons and daughters. For democracy. For Europe. For Catalonia."
The trial featured over 500 witnesses, including former prime minister Mariano Rajoy, and 50 nationally televised hearings.
Defence lawyers argued that the leaders of the secessionist movement were carrying out the will of roughly half of the 7.5 million residents of Catalonia who, opinion polls indicate, would like the region to be a separate country.