The Catalan government had paid €3m (£2.6m) in subsidies to media companies with close links to a body that claims that Shakespeare, Cervantes and Columbus – among others – were Catalan.

The figures were revealed in a parliamentary answer given by Pere Aragonès, the Catalan vice-president, who said the money had been paid since 2012 to two media companies owned by Albert Codinas, the joint founder and current president of the New History Institute (INH) – one of which shares an address with it.

Núria Llorach, the president of the body that overseas TV3, the Catalan public broadcaster, also revealed that it had paid €184,000 for the rights to screen six INH documentaries.

The programmes include claims that Spain covered up the role that Catalans played in the European discovery of the Americas, that Miguel de Cervantes, author of Don Quixote, wrote in Catalan and had his true identity disguised by the Spanish Inquisition, and that Leonardo da Vinci was Catalan.

The Cervantes documentary claims that the giant of Spanish literature was in fact Joan Miquel Sirvent, a Catalan from Alicante in south-east Spain – nowhere near Don Quixote’s La Mancha – and that “Cervantes” and Shakespeare were one and the same person. Among author Miquel Izquierdo’s abstruse arguments is that will, seré in Catalan, and am, soy, together mean “I will be and am”. According to Izquierdo, “from here it’s clear” that it refers to Sirvent.

The institute, which was founded in 2007, has produced books and documentaries that support the theory that Columbus was Catalan and that Erasmus of Rotterdam was his love child. The explorer Francisco Pizarro, who is generally believed to have started life as a swineherd in Extremadura in western Spain, has also been recruited to the Catalan pantheon, as has Saint Teresa of Ávila, the Christian mystic descended from Jewish conversos.

Mainstream Spanish historians despair at the attention given to these theories by otherwise respectable media.

Vicent Baydal, a history of law professor in Valencia and the co-author of Pseudo History Against Catalunya, said the people behind the institute “are not even [academic] historians, they’re people who have no idea, who don’t understand historical methodology and don’t even know how to look for or read historical documents”.

Gabriel Rufián, the spokesman for the pro-independence Catalan Left party, urged the region’s government to stop funding the INH last year. “No pseudoscience or pseudo-history should be funded with public money,” he said. “It only serves those who wish to portray us as small, ridiculous and angry losers.”