Judge Pablo Llarena [es; ca] had previously coordinated an instruction between October 2017 and July 2018, as a result of which 12 people were tried, including the previous vice president Oriol Junqueras of the regional government and most of the cabinet as well as political activists Jordi Sànchez and Jordi Cuixart and the former Speaker of the Parliament of Catalonia Carme Forcadell.

Prime Minister Pedro Sánchez said that he pardoned them because it was the best decision for Spain and Catalonia, but did not overturn their bans from holding public office.

After the Spanish Government refused to allow a binding referendum, pro-independence parties called for the 2015 Catalan regional election to be considered a plebiscite, with the promise to declare independence in 18 months.

On 10 October 2017, the President of the Catalan Government Carles Puigdemont addressed the Parliament of Catalonia, but did not unambiguously declare independence.

Subsequently, some of the independence leaders were sent to preventive detention without bail, accused of crimes of rebellion, disobedience, and misuse of public funds.

They are listed below in alphabetical order by their last name, indicating the accusation, the conviction requested and the sentence by the Supreme Court.

[26] The court was formed of seven members in the Criminal Chamber of the Supreme Court of Spain, chaired by Manuel Marchena: In September 2018, five of them (Manuel Marchena, Luciano Varela, Juan Ramon Berdugo, Andres Martinez Arrieta and Antonio del Moral) were recused by six of the defendants.

The first four were part of the admission room that processed, on 31 October 2017, the complaint filed by the then Attorney General of the State, José Manuel Maza.

[67] On 15 October 2018, Amnesty International requested the immediate release of the two activists Sánchez and Cuixart (known as the Jordis since they share their first name), stating that the maintenance of provisional detention was unjustified and considering it an excessive and disproportionate restriction of their rights to freedom of expression and peaceful assembly, although without referring to them as prisoners of conscience.

[75][76] In December 2018, the International Association of Democratic Lawyers issued a statement requesting the release of "Catalan political prisoners".

This initiative was promoted by the ex-presidents of the Catalan parliament Ernest Benach, Núria de Gispert and Joan Rigol.

[80] On 16 January 2019, the former presidents of the Catalan Parliament, and the Generalitat de Catalunya, along with the Ombudsman at their request, signed an official statement addressed to the Supreme Court asking them to "guarantee the right of defense for the defendants".

[83] On 30 January 2019, the vice president of the European Commission, Frans Timmermans stated that the institution has "no reasons to doubt that the right to a fair trial is guaranteed."

He added that he has no evidence pointing to "breaches of the principle of the separation of powers or issues in relation to judicial independence in Spain."

[85] On the same day, the European Democratic Lawyers association requested the "immediate" release of the Catalan leaders and expressed their "concern" due to a "lack of procedural guarantees during the trial".

[86] The day after, the International Commission of Jurists denounced the trial "unduly restricts rights of freedom of expression, assembly and association".

Nine of the twelve accused were sentenced to prison terms ranging from 9 to 13 years after being found guilty of sedition and some of them also with misuse of public funds.

[93] As soon as the verdict was made public, large crowds of protesters gathered at Barcelona-El Prat Airport following instructions by various pro-independence associations.

Though they started peacefully, some protestors began throwing small items at the police, with some in Barcelona setting fire to public litter bins.

Prime Minister Pedro Sánchez said that he pardoned them because it was the best decision for Spain and Catalonia, but did not overturn their bans from holding public office.

The leader of the conservative People's Party, Pablo Casado, reacted negatively, saying "During the [election] debate in 2019, I asked Sánchez several times whether he was going to pardon the prisoners and strike a deal with them, he denied it and promised to make holding illegal referendums a crime … He lied to Spaniards and he will have to answer at the ballot box.” The PP and other opposition parties planned to appeal the pardon.