The great Cervantes, he taught me the magic and great humanity that poetry and the music of our Golden Century harbor. In the middle of the 16th century appears in Spain the ''cross-strung harp'', as Juan de Bermudo confirms in his work, Declaration of Musical Instruments, year 1555. This appearance is due to the growing music chromatization and the progressive emancipation of the specific instrumental language. Therefore, the harp, diatonic so far, becomes a chromatic instrument in a very original way: adding an order of chromatic strings interwoven or intertwined with the diatonic ones. It turned out to be an extremely practical invention for the spanish Violeros and, apparently, not sued out of the Iberian Peninsula. The famous Tomos, witness the harp's musical intervention in these two fields, sacred and profane. One of the most prolific composers of the Tonos was Juan Hidalgo, a Royal Chapel's musician, Pedro Calderon de la Barca's right hand and, in turn, prominent harp player.