Among the estimated 30,000 letters that Unamuno wrote in his life were those written to the Machado brothers, Manuel and Antonio, at the top as recipients, although Francisco had his share.

Some dozen of these letters are preserved in the House Museum of the Rector of the University of Salamanca, but more documents keep appearing.

Pollux Hernúñez compiles in 'Los Machado y Unamuno: Cartas' (Oportet Publishers), fifty letters from the brothers of Seville and reconstructs those mentioned by Unamuno, although most of them are lost. "We must not forget that the Basque writer was at that time something similar to the Devil and that it was dangerous to have his texts at home," says the philologist.

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