The Spanish Army has existed continuously since the reign of King Ferdinand and Queen Isabella (late 15th century).

Spain entered the conflict with a strong position, but the ongoing fighting gradually eroded her advantages; first Dutch, then Swedish innovations had made the tercio more vulnerable, having less flexibility and firepower than its more modern equivalents.

Finally, in 1768 King Charles III sanctioned the "Royal Ordinances for the Regime, Discipline, Subordination, and Service in His Armies", which were in force until 1978.

In combat, small units fought well, but their old-fashioned tactics were hard to use against the French Grande Armée, despite repeated desperate efforts at last-minute reform.

[8] In 1808, Napoleon tried to depose Carlos IV of Spain and install his brother Joseph Bonaparte on the Spanish throne, sparking the Peninsular War.

[12] During these conflicts, numerous armies from Spain were dispatched to Spanish America in order to defeat the Latin American revolutionaries; these efforts proved mostly unsuccessful.

[13] As consequence of the Carlist Wars, and the weakness of the central structures of government under the Spanish monarchy, many generals with political ambitions staged coup d'états, known as pronunciamientos, which continued to occur until Bourbon Restoration in Spain under King Alfonso XII.

This period can be divided in four phases:[15] At the end of the Civil War, the Francoist (Nationalist) Army counted 1,020,500 men, in 60 divisions.

[16] During the first year of peace, Franco dramatically reduced the size of the Spanish Army to 250,000 in early 1940, with most soldiers two-year conscripts.

Concerns about the international situation, Spain's possible entry into the Second World War, and threats of invasion led Franco to undo some of these reductions.

[17] The Air Force and Navy also grew in numbers and in budgets, to 35,000 airmen and 25,000 sailors by 1945, although for fiscal reasons Franco had to restrain attempts by both services to undertake dramatic expansions.

[16] Although Spanish caudillo Francisco Franco was neutral and did not bring Spain into World War II on the side of Nazi Germany, he permitted volunteers to join the German Army (Wehrmacht) on the condition they would only fight against the Soviet Union on the Eastern Front, and not against the Western Allies or any Western European occupied populations.

Their doctrines and training were obsolete, as they had not incorporated the teachings of the Second World War; Scianna elaborates on the weaknesses of equipment, political role, and worldview.

[15] After the signing of the military agreement with the United States in 1953, the assistance received from Washington allowed Spain to procure more modern equipment and to improve the country's defence capabilities.

With the Barroso Reform (1957), the Spanish Army abandoned the organisation inherited from the Civil War to adopt the United States' pentomic structure.

1 "Brunete", the "Jarama" Cavalry Division, organized into a division HQ and four armoured groups ("agrupaciones blindadas"), three independent Armoured Brigades at rather reduced strength, and three Field Artillery Brigades ("Brigada de artillería de campaña") with assigned artillery groups.

It was to be "an army corps equipped and trained for conventional and limited nuclear warfare, ready to be deployed within or outside national borders.

"[25] It was made up of: The DOT was to maintain security in the regional commands and of reinforce the Civil Guard and the police against subversion and terrorism.

In 1973, the military education system was reformed in depth, in order to make its structure and objectives similar to those existing in the civilian universities.

The Modernización del Ejército de Tierra (META) plan was carried out from 1982 to 1988 so that Spain could achieve full compliance with NATO standards.

The reduction of the term of military service for conscripts until its complete abolition in 2001[30] and the increasing participation of Spanish forces in multinational peacekeeping operations abroad[31] were the main drivers for changes in the army after 1989.

[34] In case of a war or national emergency, an additional force of 80,000 Civil Guards comes under the Ministry of Defence command Spain Austria