The XII Army Corps was a military formation belonging to the Spanish Republican Army that fought during the Spanish Civil War. Formed by veteran units, throughout the war it took part in prominent intervention in some of the main battles of the war, such as Aragon or the Ebro.
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.[4] During the withdrawal from Aragon, the formation suffered significant losses and was undone. After the republican zone was cut in two, it was isolated in Catalonia. 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 militia major Etelvino Vega was appointed as the new commander of the XII Army Corps.[7][8]
The 16th and 44th divisions came to participate in the fighting on the Ebro, supporting the forces of the V and XV army corps. The 56th Division remained on the Segre front, where it intervened in the attacks against Vilanova de la Barca and Seròs.[9]
At the beginning of the Catalonia Offensive the XII Army Corps covered the line of the Segre River.[10] Its units, however they had a bad performance against the nationalist offensive; the 56th Division was practically disbanded, while the 16th Division was powerless to offer an organized defense.[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.
^ There are doubts about whether it was the commander of the XII Army Corps, Pedro Sánchez Plaza, the officer in command of the conquest of Belchite —whose sector was within the area assigned to the XII Army Corps.[2][3] Other sources indicate that the command would have belonged to Karol Świerczewski, commander of the 35th Division.[3]
^ In March-April 1938, a "B" Army Corps was created in the Segre area - formed by the 16th Division, which was under the command of Claudio Martín Barco; this formation later adopted the definitive numbering of "XII", receiving more reinforcement divisions.[5]