Catalonia, one of the 17 autonomous regions in Spain and one-fifth of national economic output, will vote on parting from the country Oct. 1, the head of the regional government announced June 9.
"The question will be 'do you want Catalonia to become an independent state in the form of a republic,'" Carles Puigdemont said in a speech at the regional government headquarters, according to Reuters.
Support for Catalonian independence grew as Spain slipped into financial crisis at the start of the decade, Reuters noted, although it has since slipped back. The region claims that it contributes far more to Spain's budget than it gets back.
The Spanish government has the constitutional power to block the referendum, including by suspending its regional government, Reuters noted, adding however that this would be a last-resort move and that fresh regional elections are the likeliest outcome.
Puigdemont said he had attempted to negotiate the terms of a referendum with the Madrid government, but that all his proposals had been rejected, forcing him to make a unilateral move, Reuters added.