[amiga386]

You keep saying "20th century" when the term was first popularised in the 1840s, and one scholar has traced the term back to 1795. See De la Restauración a la Reconquista: la construcción de un mito nacional (Una revisión historiográfica. Siglos XVI-XIX) https://revistas.ucm.es/index.php/ELEM/article/viewFile/ELEM... (PDF)

> the first time that the term "reconquista" was used to refer to the fight against the Muslims was in the work of José Ortíz y Sanz entitled Compendio cronológico de la historia de España, published after 1795. The use of the term, however, did not spread until the 1840s thanks to two new editions of Ortiz's work and the publication of the Historia general by Modesto Lafuente.

So the term did not originate in the 20th century, but it was added to the dictionary in 1936.

16th-19th century historians would have used the term "restoration". The northern kingdoms prosecuting this supposed restoration were keen to claim their legitimacy as a continuation of the entire Visigoth Kingdom, and made it their business to recapture it... even if they never held that territory.