1] In March 1938, at the beginning of the Aragon Offensive, the XII Army Corps had established its headquarters in Alcorisa and integrated the 24th, 30th and 44th divisions; it covered the front that ran from the Ebro river to Vivel del Río Martín.

After being briefly dissolved, the XII Corps was rebuilt[n. 2] and assigned to Ebro Army,[6] grouping within the divisions 16th, 44th and 56th.

The 56th Division remained on the Segre front, where it intervened in the attacks against Vilanova de la Barca and Seròs.

[11] As a consequence, Etelvino Vega was instantly dismissed at the beginning of January 1939, being replaced by Francisco Galán.

[12] The XII Army Corps, however, was unable to resist the enemy pressure and undertook the retreat towards the French border.