The melody of the anthem is Castillo's original though. After the Spanish Civil War, the original music scores were destroyed, and only a manuscript for piano is conserved. The composer Manuel Castillo improved José del Castillo's version.
The melody of the national anthem originated from Castillo's own creation. After the Spanish Civil War, the original sheet music was destroyed, leaving behind only a piano score. Manuel Castillo enhanced José del Castillo's initial composition.