Ángel Gregorio Villoldo Arroyo was an Argentine musician and one of the pioneers of tango music. He was lyricist, composer, and one of the major singers of the era. He is also known by the pseudonyms A. Gregorio, Fray Pimiento, Gregorio Giménez, Angel Arroyo, and Mario Reguero. Villoldo transformed the Spanish tanguillos, the cuplés, and the habaneras, turning the continental genres into native Argentinian rhythms.