The highest court in Spain has sentenced nine leaders from Catalonia to between nine and 13 years in prison because of their role in an unofficial independence referendum, which took place in 2017.
Catalonia is part of Spain, but it is a semi-autonomous region. This means that it can make some of its own decisions, but not all. It is home to about 7.5 million people and has its own language, parliament, flag and anthem.
Many people feel that Catalonia should have more independence from Spain, which currently controls its taxes. But many others disagree and think that Spain should remain united. It is an argument that has been going on in Spain for several years.
In October 2017, an unofficial vote was held in Catalonia by pro-independence leaders about this.
Now, nine of them have been imprisoned for something called sedition, while three others were found guilty of disobedience and fined. (Sedition means behaviour or language which encourages rebellion against the constituted authority in a state, or a movement designed to overthrow an established government.)
The group of 12 pictured above - some of whom had important jobs in Catalonia's parliament, while others were activists - denied the charges against them.
In 2017, Catalonia's pro-independence leaders went ahead with an unofficial referendum asking people whether or not they wanted Catalonia to be independent.
This was despite the fact that the government in Spain ruled it to be illegal and sent police to the region to try to stop it from happening.
It was reported that 2.2 million people voted and, according to the Catalan authorities, just under 90% backed independence.
There were lots of protests after people disagreed with the violent way that the police tried to stop what was happening.
Three weeks after the banned vote, the Catalan parliament declared the region to be an independent republic.
As a result, Madrid took back control of Catalonia, and many of the independence leaders fled or were arrested.
Former Catalan president Carles Puigdemont fled the country after the referendum and he is now based in Belgium.
Oriol Junqueras - the former vice-president of Catalonia and the highest-ranking pro-independence leader - received the longest sentence of 13 years for sedition and misuse of public funds.
In response, he said that Spain was putting people in prison because of their political beliefs and that the separatists would come back even stronger than last time.
Spain's Prime Minister Pedro Sanchez said the pro-independence leaders had been jailed for criminal conduct.
Many of the independence group's supporters have taken to the streets in Catalonia's capital city of Barcelona in protest against the result, with more police being used in order to keep the peace.
In September, there was an annual march in Barcelona in support of Catalonia's independence from Spain. Around 600,000 people showed up, which was one of the lowest turnouts in the rally's eight-year history.