On Sept. 12, the CIA revised its official estimate of the total number of Islamic State militants in Iraq and Syria upward almost threefold to between 20,000 and 31,500 combatants. This new number brings the CIA assessment in line with Stratfor’s long-standing estimate of 10,000 to 20,000 core Islamic State fighters in Syria alone. More important, fighters whose homelands are elsewhere have come to numerically dominate the Islamic State’s ranks. Around 12,000 foreigners, according to the recent CIA assessment, have successfully joined the Islamic State and to a lesser degree other jihadist groups in the region. Of these, 2,000 are Europeans, according to EU estimates.
These foreign fighters possess a degree of fanaticism and, in many cases, combat experience that provides the Islamic State with a powerful weapon, allowing them a major role on the battlefield. The flow of these foreign fighters into Syria and the broader Middle East has been the largest and most important influx into any region since the end of the Cold War. This phenomenon, however, is not new, and in fact has roots stretching back to the earliest recorded history. Islamic State foreign combatants are only the most recent in a long line of individuals with motivations to fight ranging from the religious to the merely economic.
Local combat forces have taken on men and women from abroad for thousands of years. These foreign fighters are distinguished from invading foreign armies in that they often travel individually or in small bands with origins in a variety of countries, regions and tribes and are generally outnumbered by both allied and enemy forces. It is only in rare cases, such as that of the Islamic State, that these fighters manage to take a dominant position on the battlefield. Even in the Islamic State, however, local Iraqis still retain most top leadership positions because the group originated and developed in Iraq and among Iraqis.
Foreign fighters throughout history have been driven by a number of factors ranging from material motivations of payment and plunder to ideological motivations that include religious and political conviction. Some simply desire adventure and a sense of purpose, camaraderie and belonging.
Some of the oldest forms of motivation for foreign fighter have been extrinsic. The term “mercenary” describes anyone specially recruited for combat and motivated primarily by monetary compensation. Often these are foreigners, providing some of the earliest historical examples of foreign fighters. As far back as the 13th century B.C., Egyptian Pharaohs employed mercenary forces recruited from the surrounding region. Persian Emperor Darius III hired Greek mercenaries in the fourth century B.C., while Carthage recruited sling shooters from the Balearic Islands as well as “barbarian” cavalry of various origins to assist against its rival, Rome. The Byzantine Greek military later relied partly on the Scandinavian Varangian Guard. And in 1346, the allied French cavalry hacked and trampled their own Genoese mercenary crossbowmen at the Battle of Crecy. In modern times, mercenary fighters continue to figure prominently in combat, especially in African nations, where both governments and warlords often employ foreign-trained pilots, specialists and soldiers of fortune.
Compensation for foreign fighters, however, can go beyond money, equipment or land. Foreign soldiers have just as often been granted citizenship, rank or higher social standing for their service. The Roman army enticed auxiliary forces from across the empire with offers of coveted Roman citizenship.
Throughout history, fighters have also traveled to distant theaters of war for intrinsic rewards — those that fulfilled a need for greater meaning or reinforced their values. With the worldwide spread of major monotheistic religions the role of the foreign combatant motivated by religion expanded dramatically. Emblematic of this phenomenon are large and diverse bands of Muslim fighters that flocked to the Holy Land in the 12th century to fight alongside the forces of Saladin, Sultan of Egypt and Syria, against the Crusader states established by European Christians. Saladin’s Ayyubid army consisted of locally recruited Arabs, Bedouins, Egyptians, Turkmen and Kurds but were augmented by Nubian spearmen from further up the Nile River, archers from Ethiopia, North African sailors as well as Berber and Persian cavalry. Religiously motivated Muslim volunteers, known as muttawi’ah, also joined Saladin’s forces from places as far away as Iberia. Unsurprisingly, the diverse national origins and native languages in the Ayyubid army led to significant battlefield communication difficulties.
There have also been multiple cases of small bands of non-Islamic foreign fighters that have traveled to distant lands to bolster local forces in religious conflicts. England’s Henry Bolingbroke, who later became King Henry IV, made a number of forays into the Baltic region to fight alongside Christian Teutonic forces against Pagan Lithuania in the late 14th century.
Some foreign fighters have set out from their homelands for ideological reasons other than religion. Political conviction motivated foreign fighters from all over the world, including novelist George Orwell, Albanian writer Petro Marko and former Prime Minister of Iran Shapour Bakhtiar, to flock to the International Brigades in the late 1930s to assist the Republicans against the fascists in the Spanish Civil War. Ernest Hemingway also went to Spain to report on the war. As World War II raged across Europe, foreign communist, anti-communist, fascist and anti-fascist fighters figured prominently in the Winter War, the Battle of Britain and the Eastern Front.
Modern Foreign Fighters
Established nation-states in the 20th century have also deliberately leveraged the often-powerful force of foreign fighters to serve their own interests — a practice that continues to the present. The French Foreign Legion is undoubtedly the most famous example of this and it continues to attract adherents from as far away as Mongolia and the United States. Others have existed or been established over the last century. These include the Spanish Foreigners Regiment, the plethora of colonial units that served primarily under the Allies during World War II, the numerous foreign volunteer units established under the German Waffen SS, the Israeli Lone Soldiers program and even former Libyan dictator Moammar Gadhafi’s Islamic Legion.
Modern state-organized foreign units have proven quite effective in battle, due in part to the motivations of the fighters. Many former French Legionnaires say that they did not join for the pay or food but for adventure, camaraderie or simply a cause to fight for. Esprit de corps and unit cohesion are the backbone forces ranging from the Nepalese Gurkhas to the Moroccan Goumiers.
The recent flow of foreign fighters into the Middle East, with a particular focus on the civil war in Syria, has upended the regional balance of power and presents a considerable cause for concern. The actual phenomenon of fighters leaving their homelands to fight abroad, however, is not without precedent. Indeed, as long as mankind wages war, foreign fighters will continue to play a prominent role on the world’s battlefields.