A mercenary is a person who takes part in an armed conflict who is not a national or party to the conflict and is "motivated to take part in the hostilities by desire for private gain". Mercenaries fight for money or other recompense instead of fighting for ideological interests, whether they agree with or are against the existing government. In the last century, and as reflected in the Geneva Convention, mercenaries have increasingly come to be seen as less entitled to protections by rules of war than non-mercenaries. However, whether or not a person is a mercenary may be a matter of degree, as financial and national interests may overlap.
- Laws of war
- National laws
- South Africa
- United Kingdom
- United States
- Gurkhas and the French Foreign Legion
- Private military and security companies
- Ancient Africa
- 19th and 20th centuries
- 18th to 19th centuries
- Warring States
- 15th to 18th centuries
- 20th century
- Classic era
- Medieval warfare
- 15th and 16th centuries
- 17th and 18th centuries
- 19th 21st centuries
- Syrian Uprising
- Saudi Arabian led intervention in Yemen
Laws of war
Protocol Additional GC 1977 (APGC77) is a 1977 amendment protocol to the Geneva Conventions. Article 47 of the protocol provides the most widely accepted international definition of a mercenary, though not endorsed by some countries, including the United States. The Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, (Protocol I), 8 June 1977 states:
Art 47. Mercenaries1. A mercenary shall not have the right to be a combatant or a prisoner of war. 2. A mercenary is any person who:
All the criteria (a – f) must be met, according to the Geneva Convention, for a combatant to be described as a mercenary.
According to the GC III, a captured soldier must be treated as a lawful combatant and, therefore, as a protected person with prisoner-of-war status until facing a competent tribunal (GC III Art 5). That tribunal, using criteria in APGC77 or some equivalent domestic law, may decide that the soldier is a mercenary. At that juncture, the mercenary soldier becomes an unlawful combatant but still must be "treated with humanity and, in case of trial, shall not be deprived of the rights of fair and regular trial", being still covered by GC IV Art 5. The only possible exception to GC IV Art 5 is when he is a national of the authority imprisoning him, in which case he would not be a mercenary soldier as defined in APGC77 Art 47.d.
If, after a regular trial, a captured soldier is found to be a mercenary, then he can expect treatment as a common criminal and may face execution. As mercenary soldiers may not qualify as PoWs, they cannot expect repatriation at war's end. The best known post-World War II example of this was on 28 June 1976 when, at the end of the Luanda Trial, an Angolan court sentenced three Britons and an American to death and nine other mercenaries to prison terms ranging from 16 to 30 years. The four mercenaries sentenced to death were shot by a firing squad on 10 July 1976.
The legal status of civilian contractors depends upon the nature of their work and their nationalities with respect to that of the combatants. If they have not "in fact, taken a direct part in the hostilities" (APGC77 Art 47.b), they are not mercenaries but civilians who have non-combat support roles and are entitled to protection under the Third Geneva Convention (GCIII 4.1.4).
On 4 December 1989, the United Nations passed resolution 44/34, the International Convention against the Recruitment, Use, Financing and Training of Mercenaries. It entered into force on 20 October 2001 and is usually known as the UN Mercenary Convention. Article 1 contains the definition of a mercenary. Article 1.1 is similar to Article 47 of Protocol I, however Article 1.2 broadens the definition to include a non-national recruited to overthrow a "Government or otherwise undermining the constitutional order of a State; or Undermin[e] the territorial integrity of a State;" and "Is motivated to take part therein essentially by the desire for significant private gain and is prompted by the promise or payment of material compensation..." – under Article 1.2 a person does not have to take a direct part in the hostilities in a planned coup d'état to be a mercenary.
Critics have argued that the convention and APGC77 Art. 47 are designed to cover the activities of mercenaries in post-colonial Africa and do not address adequately the use of private military companies (PMCs) by sovereign states.
The situation during the Iraq War and the continuing occupation of Iraq after the United Nations Security Council-sanctioned hand-over of power to the Iraqi government shows the difficulty of defining a mercenary soldier. While the United States governed Iraq, no U.S. citizen working as an armed guard could be classified as a mercenary because he was a national of a Party to the conflict (APGC77 Art 47.d). With the hand-over of power to the Iraqi government, if one does not consider the coalition forces to be continuing parties to the conflict in Iraq, but that their soldiers are "sent by a State which is not a Party to the conflict on official duty as a member of its armed forces" (APGC77 Art 47.f), then, unless U.S. citizens working as armed guards are lawfully certified residents of Iraq, i.e., "a resident of territory controlled by a Party to the conflict" (APGC77 Art 47.d), and they are involved with a fire-fight in the continuing conflict, they are mercenary soldiers. However, those who acknowledge the United States and other coalition forces as continuing parties to the conflict might insist that U.S. armed guards cannot be called mercenaries (APGC77 Art 47.d).
The laws of some countries forbid their citizens to fight in foreign wars unless they are under the control of their own national armed forces.
If a person is proven to have worked as a mercenary for any other country while retaining Austrian citizenship, his or her Austrian citizenship will be revoked.
In 2003, France criminalized mercenary activities, as defined by the protocol to the Geneva convention for French citizens, permanent residents and legal entities (Penal Code, L436-1, L436-2, L436-3, L436-4, L436-5). This law does not prevent French citizens from serving as volunteers in foreign forces. The law applies to military activities with a specifically mercenary motive or with a mercenary level of remuneration.
It is an offence "to recruit" German citizens "for military duty in a military or military-like facility in support of a foreign power" (§ 109h StGB). Furthermore, a German who enlists in an armed force of a state he is also citizen of risks the loss of his or her citizenship (§ 28 StAG).
In 1998, South Africa passed the Foreign Military Assistance Act that banned citizens and residents from any involvement in foreign wars, except in humanitarian operations, unless a government committee approved its deployment. In 2005, the legislation was reviewed by the government because of South African citizens working as security guards in Iraq during the American occupation of Iraq and the consequences of the mercenary soldier sponsorship case against Mark Thatcher for the "possible funding and logistical assistance in relation to an alleged attempted coup in Equatorial Guinea" organized by Simon Mann.
In the United Kingdom, the Foreign Enlistment Act 1819 and the Foreign Enlistment Act 1870 make it unlawful for British subjects to join the armed forces of any state warring with another state at peace with Britain. In the Greek War of Independence, British volunteers fought with the Greek rebels, which could have been unlawful; it was unclear whether or not the Greek rebels were a "state" per the Foreign Enlistment Act, but the law was clarified, saying that the rebels were a state. In 1896, a Privy Council report noted that there had been no prosecutions under the Foreign Enlistment Acts and considered them unenforceable.
The British government considered using the Act against British subjects fighting for the International Brigade in the Spanish Civil War and the FNLA in the Angolan Civil War, though in the end it chose not to on both occasions.
The Anti-Pinkerton Act of 1893 (5 U.S.C. § 3108) forbade the U.S. government from using Pinkerton National Detective Agency employees, or similar private police companies. In 1977, the United States Court of Appeals for the Fifth Circuit interpreted this statute as forbidding the U.S. government from employing companies offering "mercenary, quasi-military forces" for hire (United States ex rel. Weinberger v. Equifax, 557 F.2d 456, 462 (5th Cir. 1977), cert. denied, 434 U.S. 1035 (1978)). There is a disagreement over whether or not this proscription is limited to the use of such forces as strikebreakers, because it is stated thus:
The purpose of the Act and the legislative history reveal that an organization was "similar" to the Pinkerton Detective Agency only if it offered for hire mercenary, quasi-military forces as strikebreakers and armed guards. It had the secondary effect of deterring any other organization from providing such services lest it be branded a "similar organization." The legislative history supports this view and no other.
In the 7 June 1978 Letter to the Heads of Federal Departments and Agencies, the Comptroller General interpreted this decision in a way that carved out an exemption for "Guard and Protective Services".
A U.S. Department of Defense interim rule (effective 16 June 2006) revises DoD Instruction 3020.41 to authorize contractors, other than private security contractors, to use deadly force against enemy armed forces only in self-defense (71 Fed. Reg. 34826). Per that interim rule, private security contractors are authorized to use deadly force when protecting their client's assets and persons, consistent with their contract's mission statement. One interpretation is that this authorizes contractors to engage in combat on behalf of the U.S. government. It is the combatant commander's responsibility to ensure that private security contract mission statements do not authorize performance of inherently governmental military functions, i.e. preemptive attacks or assaults or raids, etc.
Otherwise, civilians with U.S. Armed Forces lose their law of war protection from direct attack if and for such time as they directly participate in hostilities. On 18 August 2006, the U.S. Comptroller General rejected bid protest arguments that U.S. Army contracts violated the Anti-Pinkerton Act by requiring that contractors provide armed convoy escort vehicles and labor, weapons, and equipment for internal security operations at Victory Base Complex, Iraq. The Comptroller General reasoned the act was unviolated, because the contracts did not require contractors to provide quasi-military forces as strikebreakers. Yet, on 1 June 2007, The Washington Post reported: "A federal judge yesterday ordered the military to temporarily refrain from awarding the largest security contract in Iraq. The order followed an unusual series of events set off when a U.S. Army veteran, Brian X. Scott, filed a protest against the government practice of hiring what he calls mercenaries, according to sources familiar with the matter." Though Scott had filed the protest at the Court of Federal Claims, the court order was the result of other bidders intervening in the case. Scott did not submit a bid; however, when the bidders who did submit a bid tried to protest at the GAO, their GAO bid protests were dismissed due to the fact that Scott had filed a case at the court and deprived the GAO of further jurisdiction in the matter. Scott's case had been dismissed at the GAO and was eventually dismissed at the court. The court order was in response to one of the legitimate contractors and Brian X. Scott had no role in obtaining that order.
The contract, worth about $400 million, calls for a private company to provide intelligence services to the U.S. Army and security for the Army Corps of Engineers on reconstruction work in Iraq. The case, which is being heard by the U.S. Court of Federal Claims, puts on trial one of the most controversial and least understood aspects of the Iraq war: the outsourcing of military security to an estimated 20,000 armed contractors.
Gurkhas and the French Foreign Legion
The better-known combat units in which foreign nationals serve in another country's armed forces are the Gurkha regiments of the British and Indian armies, and the French Foreign Legion.
Foreign and commonwealth nationals recruited from countries of the Commonwealth of Nations in the British Army swear allegiance to the British monarch and are liable to operate in any unit. Gurkhas, however, operate in dedicated Gurkha units of the British Army (specifically units that are administered by the Brigade of Gurkhas) and the Indian Army. However, although they are nationals of Nepal, a country that is not part of the Commonwealth, they still swear allegiance (either to the Crown or the Constitution of India) and abide the rules and regulations under which all British or Indian soldiers serve. French Foreign Legionnaires serve in the French Foreign Legion, which deploys and fights as an organized unit of the French Army. This means that as members of the armed forces of Britain, India, and France these soldiers are not classed as mercenary soldiers per APGC77 Art 47.e and APGC77 Art 47.f.
Private military and security companies
The private military company (PMC) is the contemporary strand of the mercenary trade, providing logistics, soldiers, military training, and other services. Thus, PMC contractors are civilians (in governmental, international, and civil organizations) authorized to accompany an army to the field; hence, the term civilian contractor. Nevertheless, PMCs may use armed force, hence defined as: "legally established enterprises that make a profit, by either providing services involving the potential exercise of [armed] force in a systematic way and by military means, and/or by the transfer of that potential to clients through training and other practices, such as logistics support, equipment procurement, and intelligence gathering."
Private paramilitary forces are functionally mercenary armies, not security guards or advisors; however, national governments reserve the right to control the number, nature, and armaments of such private armies, arguing that, provided they are not pro-actively employed in front-line combat, they are not mercenaries. That said, PMC "civilian contractors" have poor repute among professional government soldiers and officers—the U.S. Military Command have questioned their war zone behavior. In September 2005, Brigadier General Karl Horst, deputy commander of the Third Infantry Division charged with Baghdad security after the 2003 invasion, said of DynCorp and other PMCs in Iraq: "These guys run loose in this country and do stupid stuff. There's no authority over them, so you can't come down on them hard when they escalate force... They shoot people, and someone else has to deal with the aftermath. It happens all over the place."
If PMC employees participate in pro-active combat, the press calls them mercenaries, and the PMCs mercenary companies. In the 1990s, the media identified four mercenary companies:
In 2004 the PMC business was boosted when the U.S. and Coalition governments hired them for security in Iraq. In March 2004, four Blackwater USA employees escorting food supplies and other equipment were attacked and killed in Fallujah, in a videotaped attack; the killings and subsequent dismemberment were a cause for the First Battle of Fallujah. Afghan war operations also boosted the business.
In 2006, a U.S. congressional report listed a number of PMCs and other enterprises that have signed contracts to carry out anti-narcotics operations and related activities as part of Plan Colombia. DynCorp was among those contracted by the State Department, while others signed contracts with the Defense Department. Other companies from different countries, including Israel, have also signed contracts with the Colombian Defense Ministry to carry out security or military activities.
The United Nations disapproves of PMCs (still, the UN hired Executive Outcomes for African logistic support work). The question is whether or not PMC soldiers are as accountable for their war zone actions. A common argument for using PMCs (used by the PMCs themselves), is that PMCs may be able to help combat genocide and civilian slaughter where the UN is unwilling or unable to intervene.
In February 2002, a British Foreign and Commonwealth Office (FCO) report about PMCs noted that the demands of the military service from the UN and international civil organizations might mean that it is cheaper to pay PMCs than use soldiers. Yet, after considering using PMCs to support UN operations, the UN Secretary General, Kofi Annan, decided against it.
In October 2007, the United Nations released a two-year study that stated, that although hired as "security guards", private contractors were performing military duties. The report found that the use of contractors such as Blackwater was a "new form of mercenary activity" and illegal under International law. Many countries, including the United States and the United Kingdom, are not signatories to the 1989 United Nations Mercenary Convention banning the use of mercenaries. A spokesman for the U.S. Mission to U.N. denied that Blackwater security guards were mercenaries, saying "Accusations that U.S. government-contracted security guards, of whatever nationality, are mercenaries is inaccurate and demeaning to men and women who put their lives on the line to protect people and facilities every day."
In 2013, security firm G4S is reported to be the second largest private employer in the world.
An early recorded use of foreign auxiliaries dates back to Ancient Egypt, the thirteenth century BC, when Pharaoh Ramesses II used 11,000 mercenaries during his battles. A long established foreign corps in the Egyptian forces were the Medjay—a generic term given to tribal scouts and light infantry recruited from Nubia serving from the late period of the Old Kingdom through that of the New Kingdom. Other warriors recruited from outside the borders of Egypt included Libyan, Syrian and Canaanite contingents under the New Kingdom and Sherdens from Sardinia who appear in their distinctive horned helmets on wall paintings as body guards for Ramesses II. Celtic mercenaries were greatly employed in the Greek world (leading to the sack of Delphi and the Celtic settlement of Galatia). The Greek rulers of Ptolemaic Egypt, too, used Celtic mercenaries. Carthage was unique for relying primarily on mercenaries to fight its wars.
19th and 20th centuries
In the 20th century, mercenaries in conflicts on the continent of Africa have in several cases brought about a swift end to bloody civil war by comprehensively defeating the rebel forces. There have been a number of unsavory incidents in the brushfire wars of Africa, some involving recruitment of naïve European and American men "looking for adventure".
Many of the adventurers in Africa who have been described as mercenaries were in fact ideologically motivated to support particular governments, and would not fight "for the highest bidder". An example of this was the British South Africa Police (BSAP), a paramilitary, mounted infantry force formed by the British South Africa Company of Cecil Rhodes in 1889–1890 that evolved and continued until 1980.
Famous mercenaries in Africa include:
The Congo Crisis (1960–1965) was a period of turmoil in the First Republic of the Congo that began with national independence from Belgium and ended with the seizing of power by Joseph Mobutu. During the crisis, mercenaries were employed by various factions, and also at times helped the United Nations and other peace keepers.
In 1960 and 1961, Mike Hoare worked as a mercenary commanding an English-speaking unit called "4 Commando" supporting a faction in Katanga, a province trying to break away from the newly independent Congo under the leadership of Moïse Tshombe. Hoare chronicled his exploits in his book the Road to Kalamata.
In 1964 Moïse Tshombe (then Prime Minister of Congo) hired Major Hoare to lead a military unit called "5 Commando" made up of about 300 men, most of whom were from South Africa. The unit's mission was to fight a rebel group called Simbas, who already had captured almost two thirds of the country. Hoare chronicled his exploits in his books Congo Mercenary and Congo Warriors.
In Operation Dragon Rouge, "5 Commando" worked in close cooperation with Belgian paratroopers, Cuban exile pilots, and CIA hired mercenaries. The objective of Operation Dragon Rouge was to capture Stanleyville and save several hundred civilians (mostly Europeans and missionaries) who were hostages of the Simba rebels. The operation saved many lives; however, the Operation damaged the reputation of Moïse Tshombe as it saw the return of white mercenaries to the Congo soon after independence and was a factor in Tshombe's loss of support from president of Congo Joseph Kasa-Vubu who dismissed him from his position
At the same time Bob Denard commanded the French-speaking "6 Commando", "Black Jack" Schramme commanded "10 Commando" and William "Rip" Robertson commanded a company of anti-Castro Cuban exiles.
Later, in 1966 and 1967, some former Tshombe mercenaries and Katangese gendarmes staged the Mercenaries' Mutinies.
Mercenaries fought for the Biafrans in the Fourth Commando Brigade during the Nigerian Civil War (1967–1970). Other mercenaries flew aircraft for the Biafrans. In October 1966, for example, a Royal Air Burundi DC-4M Argonaut, flown by mercenary Heinrich Wartski, also known as Henry Wharton, crash-landed in Cameroon with military supplies destined for Biafra.
In May 1969, Carl Gustaf von Rosen formed a squadron of five light aircraft known as the Babies of Biafra, which attacked and destroyed Nigerian jet aircraft on the ground and delivered food aid. Von Rosen was assisted by ex-RCAF fighter pilot Lynn Garrison.
In the mid-1970s, John Banks, an Englishman, recruited mercenaries to fight for the National Liberation Front of Angola (FNLA) against the Popular Movement for the Liberation of Angola (MPLA) in the civil war that broke out when Angola gained independence from Portugal in 1975. When captured, John Derek Barker's role as a leader of mercenaries in Northern Angola led the judges to send him to face the firing squad. Nine others were imprisoned. Three more were executed: American Daniel Gearhart was sentenced to death for advertising himself as a mercenary in an American newspaper; Andrew McKenzie and Costas Georgiou (the self-styled "Colonel Callan"), who had both served in the British army, were sentenced to death for murder.
Executive Outcomes employees, Captains Daniele Zanata and Raif St Clair (who was also involved in the aborted Seychelles Coup of 1981), fought on behalf of the MPLA against the National Union for the Total Independence of Angola (UNITA) in the 1990s in violation of the Lusaka Protocol.
Eritrea and Ethiopia
Both sides hired mercenaries in the Eritrean–Ethiopian War from 1998 to 2000. Russian mercenaries were believed to be flying in the air forces of both sides.
American Robert C. MacKenzie was killed in the Malal Hills in February 1995, while commanding Gurkha Security Guards (GSG) in Sierra Leone. GSG pulled out soon afterwards and was replaced by Executive Outcomes. Both were employed by the Sierra Leone government as military advisers and to train the government soldiers. It has been alleged that the firms provided soldiers who took an active part in the fighting against the Revolutionary United Front (RUF).
In 2000, the Australian Broadcasting Corporation's (ABC-TV) international affairs program Foreign Correspondent broadcast a special report "Sierra Leone: Soldiers of Fortune", focusing on former 32BN and Recce members who operated in Sierra Leone while serving for SANDF. Officers like De Jesus Antonio, TT D Abreu Capt Ndume and Da Costa were the forefront because of their combat and language skills and also the exploits of South African pilot Neall Ellis and his MI-24 Hind gunship. The report also investigated the failures of the UN Peacekeeping Force, and the involvement of mercenaries and private military contractors in providing vital support to UN operations and British military Special Operations in Sierra Leone in 1999–2000.
In August 2004 there was a plot, which later became known as the "Wonga Coup", to overthrow the government of Equatorial Guinea in Malabo. Currently eight South African apartheid-era soldiers, organised by Neves Matias (former Recce major and De Jesus Antonio former Captain in 2sai BN) with (the leader of whom is Nick du Toit) and five local men are in Black Beach prison on the island. They are accused of being an advanced guard for a coup to place Severo Moto in power. Six Armenian aircrew, also convicted of involvement in the plot, were released in 2004 after receiving a presidential pardon. CNN reported on 25 August, that:Defendant Nick du Toit said he was introduced to Thatcher in South Africa last year by Simon Mann, the leader of 70 men arrested in Zimbabwe in March suspected of being a group of mercenaries heading to Equatorial Guinea.
It was not planned, allegedly, by Simon Mann, a former SAS officer. On 27 August 2004 he was found guilty in Zimbabwe of purchasing arms, allegedly for use in the plot (he admitted trying to procure dangerous weapons, but said that they were to guard a diamond mine in DR Congo). It is alleged that there is a paper trail from him which implicates Sir Mark Thatcher, Lord Archer and Ely Calil (a Lebanese-British oil trader).
The BBC reported in an article entitled "Q&A: Equatorial Guinea coup plot":The BBC's Newsnight television programme saw the financial records of Simon Mann's companies showing large payments to Nick du Toit and also some $2m coming in – though the source of this funding they say is largely untraceable.
The BBC reported on 10 September 2004 that in Zimbabwe:[Simon Mann], the British leader of a group of 67 alleged mercenaries accused of plotting a coup in Equatorial Guinea has been sentenced to seven years in jail... The other passengers got 12 months in jail for breaking immigration laws while the two pilots got 16 months...The court also ordered the seizure of Mann's $3m Boeing 727 and $180,000 found on board.
Muammar Gaddafi in Libya was alleged to have been using mercenary soldiers during the 2011 Libyan civil war, including Tuaregs from various nations in Africa. Many of them had been part of his Islamic Legion created in 1972. Reports say around 800 had been recruited from Niger, Mali, Algeria, Ghana and Burkina Faso. In addition, small numbers of Eastern European mercenaries have also turned up supporting the Gaddafi regime. Most sources have described these troops as professional Serbian veterans of the Yugoslavia conflict, including snipers, pilots and helicopter experts. Certain observers, however, speculate that they may be from Poland or Belarus. The latter has denied the claims outright; the former is investigating them. Although the Serbian government has denied that any of their nationals are currently serving as mercenary soldiers in North Africa, five such men have been captured by anti-Gaddafi rebels in Tripoli and several others have also allegedly fought during the Second Battle of Benghazi. Most recently, a number of unidentified white South African mercenaries were hired to smuggle Gaddafi and his sons to exile in Niger. Their attempts were thwarted by NATO air activity shortly before the death of Libya's ousted strongman. Numerous reports have indicated that the team was still protecting Saif al-Islam Gaddafi shortly before his recent apprehension.
Amnesty International has claimed that such allegations against Gaddafi and the Libyan state turned out to either be false or lacking any evidence. Human Rights Watch has indicated that while many foreign migrants were erroneously accused of fighting with Gaddafi, there were also genuine mercenaries from several nations who participated in the conflict.
18th to 19th centuries
In 18th and early 19th centuries, the imperial Mughal power was crumbling and other powers, including the Sikh Misls and Maratha chiefs, were emerging. At this time, a number of mercenaries, arriving from several countries found employment in India. Some of the mercenaries emerged to become independent rulers.
Mercenaries were regularly used by the kingdoms of the Warring States period of China. Military advisers and generals trained through the works of Mozi and Sun Tzu would regularly offer their services to kings and dukes.
After the Qin conquest of the Warring States, the Qin and later Han Empires would also employ mercenaries – ranging from nomadic horse archers in the Northern steppes or soldiers from the Yue kingdoms of the South. The 7th century Tang Dynasty was also prominent for its use of mercenaries, when they hired Tibetan and Uyghur soldiers against invasion from the Göktürks and other steppe civilizations.
15th to 18th centuries
The Saika mercenary group of the Kii Province, Japan, played a significant role during the Siege of Ishiyama Hongan-ji that took place between August 1570 to August 1580. The Saikashuu were famed for the support of Ikkō Buddhist sect movements and greatly impeded the advance of Oda Nobunaga's forces.
Ninjas were peasant farmers who learned the art of war to combat the daimyō's samurai. They were hired out by many as mercenaries to perform capture, infiltration and retrieval, and, most famously, assassinations. Ninjas possibly originated around the 14th century, but were not widely known or used till the 15th century and carried on being hired till the mid 18th century.
In 1615, the Dutch invaded the Ai Island with Japanese mercenaries.
In the warlord period of China, many American and British mercenaries thrived such as Homer Lea, Philo Norton McGriffin, Morris "Two Gun" Cohen, and Francis Arthur "One Armed" Sutton.
During the early stages of the Second Sino-Japanese War, a number of foreign pilots served in the Chinese Air Force, most famously in the 14th Squadron, a light bombardment unit often called the International Squadron, which was briefly active in February and March 1938.
The United States could not become overtly involved in the conflict, due to Congressional restrictions, yet felt an obligation to assist the Chinese in stopping Japanese aggression. So in 1941 the Roosevelt administration authorized the formation of three American Volunteer Groups, of which the 1st AVG was deployed to Burma and China and became famous as the Flying Tigers. The pilots earned $600–$750 basic pay per month, plus $500 for each Japanese aircraft confirmed destroyed in the air or on the ground. The 2nd AVG, a bomber group, was recruited in November 1941 but aborted following the Japanese attack on Pearl Harbor.
Many Greek mercenaries fought for the Persian Empire during the early classic era. For example:
In the late Roman Empire, it became increasingly difficult for Emperors and generals to raise military units from the citizenry for various reasons: lack of manpower, lack of time available for training, lack of materials, and, inevitably, political considerations. Therefore, beginning in the late 4th century, the empire often contracted whole bands of barbarians either within the legions or as autonomous foederati. The barbarians were Romanized and surviving veterans were established in areas requiring population. The Varangian Guard of the Byzantine Empire is the best known formation made up of barbarian mercenaries (see next section).
Byzantine Emperors followed the Roman practice and contracted foreigners especially for their personal corps guard called the Varangian Guard. They were chosen among war-prone peoples, of whom the Varangians (Norsemen) were preferred. Their mission was to protect the Emperor and Empire and since they did not have links to the Greeks, they were expected to be ready to suppress rebellions. One of the most famous guards was the future king Harald III of Norway, also known as Harald Hardrada ("Hard-counsel"), who arrived in Constantinople in 1035 and was employed as a Varangian Guard. He participated in eighteen battles and was promoted to akolythos, the commander of the Guard, before returning home in 1043. He was killed at the Battle of Stamford Bridge in 1066 when his army was defeated by an English army commanded by King Harold Godwinson.
In England at the time of the Norman Conquest, Flemings (natives of Flanders) formed a substantial mercenary element in the forces of William the Conqueror with many remaining in England as settlers under the Normans. Contingents of mercenary Flemish soldiers were to form significant forces in England throughout the time of the Norman and early Plantagenet dynasties (11th and 12th centuries). A prominent example of these were the Flemings that fought during the English civil wars, known as the Anarchy or the Nineteen-Year Winter (AD 1135 to 1154), under the command of William of Ypres, who was King Stephen's chief lieutenant from 1139 to 1154 and who was made Earl of Kent by Stephen.
In Italy, the condottiero was a military chief offering his troops, the condottieri, to city-states. During the ages of the Taifa kingdoms of the Iberian peninsula, Christian knights like El Cid could fight for some Muslim ruler against his Christian or Muslim enemies. The Almogavars originally fought for Catalonia and Aragon, but as the Catalan Company, they followed Roger de Flor in the service of the Byzantine Empire. Catalan and German mercenaries also had prominent role in the Serbian victory over Bulgarians in the Battle of Velbuzd in 1330.
During the later Middle Ages, Free Companies (or Free Lances) were formed, consisting of companies of mercenary troops. Nation-states lacked the funds needed to maintain standing forces, so they tended to hire free companies to serve in their armies during wartime. Such companies typically formed at the ends of periods of conflict, when men-at-arms were no longer needed by their respective governments. The veteran soldiers thus looked for other forms of employment, often becoming mercenaries. Free Companies would often specialize in forms of combat that required longer periods of training that was not available in the form of a mobilized militia. The White Company commanded by Sir John Hawkwood is the best known English Free Company of the 14th century. Between the 13th and 17th Century the Gallowglass fought within the Islands of Britain and also mainland Europe. A Welshman Owain Lawgoch (Owain of the Red Hand) formed a free company and fought for the French against the English during the Hundred Years' War, before being assassinated by a Scot by the name of Jon Lamb under the orders of the English Crown in 1378 during the siege of Mortagne.
15th and 16th centuries
Swiss mercenaries were sought during the late 15th and early 16th centuries as being an effective fighting force, until their somewhat rigid battle formations became vulnerable to arquebuses and artillery being developed at the same time. See Swiss Guard.
It was then that the German landsknechts, colorful mercenaries with a redoubtable reputation, took over the Swiss forces' legacy and became the most formidable force of the late 15th and throughout the 16th century, being hired by all the powers in Europe and often fighting at opposite sides. Sir Thomas More in his Utopia advocated the use of mercenaries in preference to citizens. The barbarian mercenaries employed by the Utopians are thought to be inspired by the Swiss mercenaries.
A class of mercenaries known as the Gallowglass dominated warfare in Ireland and Scotland between the 13th and 16th centuries. They were a heavily armed and armored elite force that often doubled as a chieftain's bodyguard.
At approximately the same period, Niccolò Machiavelli argued against the use of mercenary armies in his book of political advice The Prince. His rationale was that since the sole motivation of mercenaries is their pay, they will not be inclined to take the kind of risks that can turn the tide of a battle, but may cost them their lives. He also noted that a mercenary who failed was obviously no good, but one who succeeded may be even more dangerous. He astutely pointed out that a successful mercenary army no longer needs its employer if it is more militarily powerful than its supposed superior. This explained the frequent, violent betrayals that characterized mercenary/client relations in Italy, because neither side trusted the other. He believed that citizens with a real attachment to their home country will be more motivated to defend it and thus make much better soldiers.
The Stratioti or Stradioti (Italian: Stradioti or Stradiotti; Greek: Στρατιώτες, Stratiotes) were mercenary units from the Balkans recruited mainly by states of southern and central Europe from the 15th until the middle of the 18th century. The stradioti were recruited in Albania, Greece, Dalmatia, Serbia and later Cyprus. Most modern historians have indicated that the Stratioti were mostly Albanians. According to a study by a Greek author, around 80% of the listed names attributed to the stradioti were of Albanian origin while most of the remaining ones, especially those of officers, were of Greek origin; a small minority were of South Slavic origin. Among their leaders there were also members of some old Byzantine Greek noble families such as the Palaiologi and Comneni. The stratioti were pioneers of light cavalry tactics during this era. In the early 16th century heavy cavalry in the European armies was principally remodeled after Albanian stradioti of the Venetian army, Hungarian hussars and German mercenary cavalry units (Schwarzreitern). They employed hit-and-run tactics, ambushes, feigned retreats and other complex maneuvers. In some ways, these tactics echoed those of the Ottoman sipahis and akinci. They had some notable successes also against French heavy cavalry during the Italian Wars. They were known for cutting off the heads of dead or captured enemies, and according to Commines they were paid by their leaders one ducat per head.
17th and 18th centuries
During the 17th and 18th century extensive use was made of foreign recruits in the now regimented and highly drilled armies of Europe, beginning in a systematized way with the Thirty Years' War. The historian Geoffrey Parker notes that 40,000 Scotsmen (about fifteen percent of the adult male population) served as soldiers in Continental Europe from 1618 to 1640. After the signing of the Treaty of Limerick (1691) the soldiers of the Irish Army who left Ireland for France took part in what is known as the Flight of the Wild Geese. Subsequently, many made a living from working as mercenaries for continental armies, the most famous of whom was Patrick Sarsfield, who, having fallen mortally wounded at the Battle of Landen fighting for the French, said "If this was only for Ireland".
About a third of the infantry regiments of the French Royal Army prior to the French Revolution were recruited from outside France. The largest single group were the twelve Swiss regiments (including the Swiss Guard). Other units were German and one Irish Brigade (the "Wild Geese") had originally been made up of Irish volunteers. By 1789 difficulties in obtaining genuinely Irish recruits had led to German and other foreigners making up the bulk of the rank and file. The officers however continued to be drawn from long established Franco-Irish families. During the reign of Louis XV there were also a Scottish (Garde Écossaise), a Swedish (Royal-Suédois), an Italian (Royal-Italien) and a Walloon (Horion-Liegeois) regiments recruited outside the borders of France. The foreign infantry regiments comprised about 20,000 men in 1733, rising to 48,000 at the time of the Seven Years' War and being reduced in numbers thereafter.
In Italy, during inter-family conflicts such as the Wars of Castro, mercenaries were widely used to supplement the much smaller forces loyal to particular families. Often these were further supplemented by troops loyal to particular duchies which had sided with one or more of the belligerents.
During the American Revolution, King George III of England, hired German mercenary soldiers from some of the German principalities to supplement his Royal Army. Although the German mercenaries came from a number of states, the majority came from the German state of Hesse-Kassel. This resulted in their American opponents referring to all of King George's German mercenaries as "Hessians", whether the Germans were actually from Hesse-Kassel or not.
The Spanish Army also made use of permanently established foreign regiments. These comprised three Irish regiments (Irlanda, Hiberni and Ultonia); one Italian (Naples) and five Swiss (Wimpssen, Reding, Betschart, Traxer and Preux). In addition one regiment of the Royal Guard including Irishmen as Patten, McDonnell and Neiven, was recruited from Walloons. The last of these foreign regiments was disbanded in 1815, following recruiting difficulties during the Napoleonic Wars. One complication arising from the use of non-national troops occurred at the Battle of Bailén in 1808 when the "red Swiss" (so-called from their uniforms) of the invading French Army clashed bloodily with "blue Swiss" in the Spanish service.
The Atholl Highlanders, a private Scottish infantry regiment of the Duke of Atholl, was formed in 1839 purely for ceremonial purposes. It was granted official regimental status by Queen Victoria in 1845 and is the only remaining legal private army in Europe.
The Free Syrian Army claimed the Bashar al-Assad regime recruited mercenaries from Iran, Hezbollah militia and the Iraqi Mahdi Army militia during the Syrian uprising.
Saudi Arabian-led intervention in Yemen
During Decisive Storm, Army of the United Arab Emirates hired hundreds foreign mercenaries from Latin America, Sudan and Eritrea by Black Water security company and sent them to fight against Houthis.