It became known as People's Army of the Republic (Ejército Popular de la República) after it was reorganized, following the disbandment of the voluntary militias that were formed in July 1936 at the beginning of the Spanish Civil War.

The Spanish Republican Army went through two clear phases during its existence: Following the loss of Spain's last colonies, Cuba and Philippines, in 1898, the country's armed forces grew disgruntled and the public's view toward them worsened.

[2] In November 1905 Spanish Army personnel stormed the offices of Catalan magazine Cu-Cut!, where En Patufet and La Veu de Catalunya were also located, for having published a caricature ridiculing the military.

The Tragic Week protests in Barcelona in July 1909, which quickly turned anticlerical, were primarily the result of the unpopular Moroccan wars that "merely satisfied the needs of the Military" in the eyes of the public.

Allegedly the aim of the Juntas de Defensa was to defend the interests of Spanish military officers, but their intention to get involved in political issues was clear to the public.

[13] Officers such as Gonzalo Queipo de Llano and Ramón Franco with a background in the pro-republican Jaca and Cuatro Vientos-Getafe uprisings during the monarchy rose to high posts for which they were not the most competent.

He led a group of officers opposed to the military reforms, as well as to the policy of granting autonomy to Catalonia and the Basque Country which they resented as an "affront to the unity of Spain".

[16] After the partly successful coup of the pro-fascist generals in July 1936, militias were formed in many cities in Spain that had not sided with the rebellion lest the units of the Spanish Republican Army stationed in their territory be tempted to join the rebels.

[16] Finally in October the Republican government reorganized its armed forces around the military units that had remained loyal and the militias were merged with the new army.

[17] By means of this new structure, the Regular Popular Army unified all the branches of the military, including the Fifth Regiment, as well as all scattered militias, a process that was gradually implemented with the goal of completion by February 1937.

The new Republican People's Army instituted the Comisariado de Guerra[19] by means of which political commissars were charged with the mission of lifting the morale of the troops and ensuring their cooperation with their high-rank officers in all units.

Based on a model that would replace the columns (columnas) and militias, the Mixed Brigade (Brigada mixta) was the basic military unit of the Republican People's Army.

They distrusted the Communist leadership and perceived the move as an effort to force them to abandon their militia model, making them depend from a single central power, which was against their ideals.

The Soviet Union, profiting from the international isolation of the Spanish Republic imposed by the Non-intervention agreements, assisted the beleaguered Republican government chiefly by providing weapons.

Despite the fact that the Soviet arms shipments were duly paid at high prices, the USSR used this opportunity to extend its power over the Spanish Republic.

In April 1938 Socialist minister of defense Indalecio Prieto resigned in protest at the level of Soviet influence over the Spanish Republican Army.

Very young soldiers, averaging 17 and a half in age, whose unit was known as the 'Baby bottle conscription' ("quinta del biberón") would be mobilized for this last big battle of the Civil War, the last one in which the International Brigades operated.

[16] Opposed by high-ranking officers such as republican Catholic general Vicente Rojo Lluch, 'Stalinist' influence only abated right at the end of the Civil War with the creation of a National Defence Council (Consejo Nacional de Defensa) by Segismundo Casado, commander of the Central Army, and Julián Besteiro.

[28] Finally, there was a smaller group of men which scattered and hid in the mountainous areas of Spain, such as the Montes de Toledo, the Galician Massif, the Pyrenees and the cordilleras of the Iberian System.

Most of the foreign volunteer combatants would be part of the International Brigades' (Brigadas internacionales) own sections until they were asked to withdraw in order to satisfy the demands of the Non-Intervention Committee in the fall of 1938.

After the Spanish Republican territory was split in two in April 1938, there was an emergency reorganization of the military units that implied deep changes both in the structure as well as in the general distribution of the remaining battle-ready armies.

Shortly thereafter the Aeronáutica Naval, the air branch of the Spanish Navy, already established through a Royal decree four years earlier, became functional in El Prat, in the same location as present-day Barcelona Airport.

Captain Cipriano Rodríguez Díaz and Lieutenant Carlos de Haya González flew non-stop to Equatorial Guinea, then a Spanish colonial outpost.

Under Capitan Warlela cadastral surveys of Spain were carried out using modern methods of aerial photography in 1933 and the following year Commander Eduardo Sáenz de Buruaga became new chief-commander of the Aeronáutica Militar.

The republican forces of the Spanish Civil War used three-pointed stars were placed below the rank insignia of officers assigned to the command of units above the size of regiment.