According to the Geographic Dictionary, published in Barcelona in 1830, Entrena it would be founded by this king around 750, but already it is known by the Chronicle of Alfonso III that these incursions realised by this king did not suppose the foundation of villages.
Segundo o Dicionario Xeográfico, editado en Barcelona en 1830, Entrena sería fundada por este rei contra o ano 750, pero xa se sabe pola Crónica de Afonso III que as incursións realizadas por este rei non supuxeron a fundación de vilas.