Juan Martín Díez, Spanish general (d. 1825)
Juan Martín Díez, nicknamed El Empecinado (Spanish: the Undaunted), (5 September 1775 – 20 August 1825) was a Spanish military leader and guerrilla fighter, who fought in the Peninsular War.

On October 8, 1808, the privilege of using the name Empecinado was granted to Juan Martín Díez, not only for himself, but also all his descendants. His nickname has given the Spanish language the verb empecinarse, meaning to persist or insist on achieving one's goals.