They are composed of: the Army, the Air and Space Force, the Navy, the Royal Guard, and the Military Emergencies Unit, as well as the so-called Common Corps.

After the long Reconquista ending in 1492, Spain evolved into Europe's foremost power with the voyages of Christopher Columbus the same year, leading to Spain acquiring vast lands in the Americas and conquering a number of overseas civilizations in the decades to come.

The period of reconquest of Iberia had ended, and now Spain entered an era of overseas conquest spearheaded by conquistadors.

Recently, in the last decades of the 20th century and the first decades of the 21st, Spanish troops have participated together with their Western allies in operations such as Gulf War, NATO bombing of Yugoslavia, KFOR, War on terror, 2011 military intervention in Libya, Combined Task Force 150 or UNIFIL, to name a few examples.

Spain participated along with France, the United Kingdom, Italy, Denmark, the United States and Canada in the 2011 intervention against Muammar Gaddafi in Libya, contributing a tanker, 4 F/A-18 Hornet fighter jets, a frigate, a submarine and a surveillance aircraft, along with logistical support from the Naval Station Rota and the Morón Air Base.

As of June 2017, 3,093 soldiers of the Spanish Armed Forces and the Civil Guard are part of the nineteen operations where Spain has an active role.

[6] According to the National Security Department of Spain (DSN), these are the current missions of the armed forces and civil guard: [6] The Spanish Armed Forces also participated in the last few years in other missions, above all humanitarian and observation: in Albania in 1999, Mozambique in 2000, Republic of Macedonia in 2001, Haiti in 2004 and Indonesia in 2005.

Spain also participated in the Iraq War between 2003 and 2004, in Gabon and in Senegal to safeguard maritime traffic in the Horn of Africa (with 33 Civil Guards and national police officers, two patrol vessels and a helicopter).

[7] In 2015, 46 UME soldiers and 12 Civil Guards of the High Mountain Group went to help and rescue in the Nepal earthquake, along with six dogs, three scientific police and a Boeing 707 of supplies transport of the Air and Space Force.

The President of the Government (also known as Prime Minister in English translations), as the head of government, is responsible under article 97 for "domestic and foreign policy, civil and military administration and the defense of the State", and thus bears the ultimate responsibility before the Cortes Generales, and the Spanish electorate.

No provision in the Constitution requires the Government to seek approval from the Cortes Generales before sending the armed forces abroad.

The country also has the 77,000 strong Civil Guard which comes under the control of the Ministry of defense in times of a national emergency.

"Groups" (midway between battalions and regiments) are stationed in Madrid and Las Palmas de Gran Canaria.

Its principal weapons include light tanks, armored combat vehicles, self-propelled artillery, and SPIKE antitank missiles.

The Spanish Air and Space Force is replacing older aircraft in the inventory with newer ones including the recently introduced Eurofighter Typhoon and the Airbus A400M Atlas airlifter.

The activities including handling natural hazards such as floods and earthquakes, forest fires, chemical and nuclear accidents, and other emergency situations recognized as such by the Prime Minister of Spain.