 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.These expeditions, carried out along with their brother Froila, consisted of killing the Muslims they found and gathering Christians to take them to the mountains.In 1044, Entrena appears documented under the romance name "Antelena".