Republican

The national anthem of Spain during The Second Spanish Republic was "Himno de Riego" (Riego's Hymn) in honour of the General and liberal politician Rafael del Riego, hero of the Spanish Civil War 1820-1823 (not the 1936-1939 one).

Using Babelfish, WordReference.com, and Thesaurus.com, and downloading the MP3 from this leftist republican site (Spanish, not Irish), one can fashion a reasonable translation that just about scans:

Riego's Hymn                                Himno de Riego

Serene and contented                    Serenos y alegres
Daring and valiant                          valientes y osados
We are singing soldiers                    cantemos soldados
Singing our songs of war.                el himno a la lid.
Our proclamation                           De nuestros acentos
Astounds other nations                   el orbe se admire
So let them behold                         y en nosotros mire
The Children of El Cid                      los hijos del Cid.

CHORUS:                                      CHORUS:
Troops of the Mother Country          Soldados la patria
She summons us to fight                 nos llama a la lid,
To her we swear our fealty              juremos por ella
Death or victory!                           vencer o morir.

The world has never witnessed        El mundo vio nunca
Such noble audacity                      más noble osadia,
Nor ever shall encounter                 ni vió nunca un día
Any greater valour                        más grande el valor,
A fire is ignited                             que aquel que, inflamados,
Burning bright inside us                  nos vimos del fuego
Inspired by Riego                          excitar a Riego
And the land that we adore            de Patria el amor

CHORUS                                     CHORUS

The trumpet of battle                   La trompa guerrera
Echos on the wind                       sus ecos da al viento,
Longing for terror                         horror al sediento,
And the boom of the canon           ya ruge el cañon
Mars, so ferocious                       a Marte, sañudo,
Provokes our boldness                  la audacia provoca
Invokes inventiveness                  y el ingenio invoca
Of our noble nation                      de nuestra nación.

CHORUS                                    CHORUS

Have fun singing along!