Los salmantinos del siglo XVI se interesaron de modo especial por la fe que todos han de creer expresamente en los tiempos todos. Se ocuparon por ello de modo especial del Apostólico; es decir, del credo breve de la fe. Fray Luis de León (1568) y Pedro de Aragón (1584) afrontan la problemática inherente al Apostólico. Muestran que las sentencias del mismo son verdaderamente de fe y han de ser creídas expresamente por todos. Ahora bien, destacan claramente que su infalibilidad y obligatoriedad universales tal por imponerlas la Iglesia.--------------------------------------------The Salamancans of the XVI century were extremely interested in the formulation of those truths which must be explicitly and universally believed by all Christians at all times. Therefore, they showed particular interest in the Apostolic Creed; that is, the short declaration of faith. Fray Luis de Leon (1568) and Pedro de Aragon (1584) confronted the questions inherent in the Creed. They declare that its statements are truly of faith and must be unmistakably believed by everyone. But however, they clearly point out that its universal infallibility and obligatory nature as such because they are imposed by the Church.