But the court ruled against definitively releasing the five, including Catalonia's former vice-president Oriol Junqueras — as demanded by their lawyers — as a trial over their role in the region's secession bid continues.
Junqueras, who led the list of his ERC separatist party, was elected to Spain's lower house in the general elections held on April 28th.
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The jailed politicians in court on the first day of trial in Madrid. Photo: AFP
Others elected to the lower house were civic leader Jordi Sanchez and Jordi Turull, Catalonia's government spokesman at the time of a failed attempt to break from Spain in October 2017.
Both were candidates for Together for Catalonia, the party of Catalonia's former president Carles Puigdemont, who fled Spain and avoided arrest.
Josep Rull, also part of Catalonia's regional government at that time, was another elected to the lower house.
Raul Romeva, in charge of Catalonia's foreign affairs at the time of the secession bid, was elected to the Senate.
All are in jail and are currently on trial in Spain's Supreme Court.
During the parliament's opening session, all MPs have to promise to comply with the Spanish constitution.
The April elections saw Prime Minister Pedro Sanchez's socialists win but without the necessary majority to govern solo in a fragmented political landscape marked by the far-right's entry into parliament.