1. Foreign Volunteering: New Trends in the Historiography

Nir Arielli

Those familiar with the history of the International Brigades in the Spanish Civil War would fnd the responses given during a Radio Free Europe interview with two foreign volunteers in Ukraine in June 2022 strangely familiar. While International Brigaders often described the war in Spain as “a chance to strike back at fascism, to prevent it spreading any further across Europe,” “Grinch,” a North American volunteer in the Ukrainian Foreign Legion, remarked that “what happens here [in Ukraine] decides what will happen to democracy all around the world.” His comrade “Jimmy” added, “[I]f they [the Russians] gain victory here, they will continue with other European countries.”[1]

The fow of foreign volunteers to Ukraine prompted many to draw comparisons with either the enlistment of foreigners in the International Brigades in Spain or the recruitment of volunteers from abroad by Finland in its war against the Soviet Union in 1939–40.[2] In the decade before the 2022 Russian attack on Ukraine, scholars were considering whether the precedent set in Spain in the 1930s holds any lessons for our understanding of the “foreign fghter” phenomenon in the civil war in Syria.[3] Such comparisons rest on the assumption that there are intrinsic commonalities between foreign volunteers in diferent historical contexts. This chapter surveys some of the main trends in the recent anglophone historiography in the feld, focusing in particular on terminology and defnitions, reasons for enlisting, wartime experiences, military contribution, postwar return, and memory.

Contested Defnitions

Who should be considered a foreign volunteer? Agreeing on a defnition or even on the terminology has not been easy. The frst book dedicated to the comparative study of the phenomenon was David Malet’s Foreign Fighters: Transnational Identity in Civil Conficts, published in 2013. Malet defnes foreign fghters as “noncitizens of confict states who join insurgencies during civil conficts.”[4] This defnition excludes foreigners who participated in stateon-state conficts such as the Second World War or the current war between Russia and Ukraine.

My own diachronic study, From Byron to bin Laden: A History of Foreign War Volunteers, published a few years later, uses a broader defnition: “Foreign volunteers leave their country of nationality or residence and take part in a confict abroad on the basis of a personal decision, without being sent by their government and not primarily for material gain.”[5] This approach allows for the inclusion of volunteers who participated in a confict but not in combat roles, such as the foreign nurses and doctors who aided the Republican war efort in Spain or Lord Byron who died in Greece in 1824 without having fought against the Ottoman Empire.

Elizabeth Grasmeder puts forward yet another term, “legionnaires,” and another defnition for us to consider: “foreigners who are neither citizens nor subjects of the state whose military they serve.”[6] Unlike Malet, who concentrates on insurgents who seek to enlist supporters from abroad, Grasmeder focuses squarely on foreigners recruited by states. Legionnaires “are uniformed personnel who serve in a state’s armed forces” and are therefore distinguishable from mercenaries or contractors who “fght outside a state’s military” and its command structure.[7] However, Grasmeder does not distinguish between foreigners who volunteer to fght for another state and those who are otherwise enticed to enlist.

Two recent studies on “lone soldiers” in the Israel Defense Forces (IDF)— diaspora Jews who travel to Israel without their families with the purpose of enlisting for military service—add fresh insights to conceptual discussions regarding the phenomenon. Timrah Schmutz suggests that we should avoid focusing strictly either on civil wars and insurgencies or on recruitment by states: “it would be erroneous—from both historical and contemporary perspectives—to connect foreign fghting to only one form of confict or one type of armed entity.” Instead, she argues that we ought to think “about the foreign-fghter phenomenon as an action (i.e. foreign fghting) rather than a label,” thereby helping us “to de-essentialize and de-culturalize it.”[8] Meanwhile, Lior Yohanani puts forward the idea that the study of foreign war volunteers would beneft from engaging with the literature on participation in voluntary high-risk collective action. Like refugee rescuers, for instance, foreign volunteers assume certain physical, social, legal, and fnancial risks as well as costs in terms of time, money, and energy. High-risk activists may choose to engage on the basis of beliefs and values, or they could “opt-in as a way out of unfavorable life circumstances.”[9] As the following section shows, a number of scholars have argued that foreign volunteers decide to join conficts abroad for very similar reasons.

Motivations

The question of what brings people to travel to another country and volunteer for transnational military service has remained central to the historiography in the feld. As recent studies have illustrated, the potential pool of volunteers is always larger—at times far larger—than the number of people who actually commit to fghting for a foreign cause. For instance, Shay Hazkani has shown that several thousands of would-be volunteers from across the Middle East registered their willingness to join the Arab Liberation Army that fought alongside the Palestinian Arabs in 1948. However, only a fraction of these—approximately 10 percent in the case of Lebanon and a mere 800 out of 15,000 in Iraq—physically made their way to fght in Palestine.[10]

So what sets those who do volunteer apart? According to Fraser Raeburn, the explanation should be sought at the local or even “microsocial” level: “the communities of the faithful from whence the vast bulk of volunteers came.” Focusing on Scottish volunteers who joined the International Brigades, he argues that the decision to volunteer “was made within a particular social and communal context, alongside friends, family and colleagues.”[11] This accounts for the “clustering among the Scottish contingent,” with volunteers often serving alongside friends and acquaintances from before the war. Furthermore, because the networks and branches of the Communist Party were constituted diferently across contexts, some hubs produced more volunteers for Spain than others.[12]

In general, recent scholarship on foreign participation in the Spanish Civil War has tended to move away from Cold War era debates about whether volunteers were “heroic anti-fascists or dupes of Moscow.”[13] Instead, more attention has been paid to how the volunteers perceived the confict in Spain as well as their personal, non-ideological reasons for enlisting. This is not to say that previous studies were oblivious to the personal motivations of volunteers. Hugh Thomas, for instance, asserted already in 1961 that “many” British volunteers who traveled to Spain did so as they “desired some outlet through which to purge some private grief or maladjustment.”[14] But recent studies have explored such issues in greater depth and produced new insights.

Judith Keene, who examines the foreign contingents that fought alongside Francoist forces, concludes that “the foreign volunteers for Franco ftted the Nationalist cause [in Spain] into the political frameworks that they had formulated in their own home contexts.”[15] Samuël Kruizinga and Miriam van der Veen assess how such frameworks were nurtured and maintained. They examine how left-wing British, Dutch, and German-language newspapers “recruited” their readers to the cause of the Spanish Republic. These newspapers not only provided information about the war in Spain, but also defned the enemy that the Spaniards and their allies in the International Brigades were facing. By doing so, the newspapers forged a connection “between ‘them’ in Spain and ‘us’, bridging the considerable physical and emotional distances that separated the Spanish Civil War and its participants from the locales where their supporters could be found.”[16]

However, foreign volunteers do not always hail from easily discernible groups. Darryl Li, who has researched the Mujahids—Muslims from abroad who fought in the war in Bosnia during the early 1990s—observes that their “motivations, orientations toward Islamic piety, and class backgrounds varied widely and confound any straightforward attempt at correlating individuals to social variables or nationalities.”[17] So what do foreigners who have taken part in diferent conficts have in common?

My own work has focused on the “push” and “pull” factors that infuenced the decision of volunteers to enlist and argues that their action should be understood as a search for meaning. Ego documents penned by volunteers and retrospective testimonies often concede that there was some sort of dissatisfaction with or void in their prewar lives. In that respect, there is a good deal of resemblance between foreign volunteers in the Spanish Civil War and those in more recent conficts. Former International Brigader Esmond Romilly observed: “However strongly I sympathised with the cause of the Spanish people, no doubt if my circumstances in London had been completely satisfactory, I should have gone no further than sympathy.” He felt that he was not alone in volunteering for a mixture of reasons: “I am assuming it will be taken for granted that everybody who joined the International Brigades had ‘political motives’; but these were not the only reason they joined.”[18] Romilly’s remarks were echoed many years later by Hunter Page, a volunteer from the United States who fought alongside Kurdish forces in Syria. In a 2019 interview with The Independent, Page pointed out:

[E]veryone who comes here and everyone who joins, it’s always a mixture of political and personal reasons. I mean, if we had great home lives with wonderful spouses and great jobs, I don’t think even the most radical political people could easily come here.[19]

A mixture of moral and personal reasons for enlisting can also be observed among the foreign volunteers who traveled to Ukraine in 2022. For instance, “James,” a British volunteer, told The Guardian: “They [the Ukrainians] needed help, and I was doing nothing back at home. My life was going downhill so I thought I could do something better and help people who needed it.”[20] The search for meaning and a sense of purpose, I argue, is a common denominator among foreign volunteers in diferent conficts and at diferent times.

Nerina Weiss, who has researched foreign volunteers who joined Kurdish armed groups in Syria, Iraq, and Turkey, goes one step further. She argues that ideology is neither a precondition nor a necessary reason for the volunteers’ initial mobilization: “ideology often does not even produce a sufciently strong enough (imagined) community to persuade them to sacrifce their individual interests for a group or organisation with whom they have neither history nor culture in common.”[21] While there certainly was a will to fght against the Islamic State from the outset, an alignment with the ideology of Kurdish organizations often only came following and as a result of mobilization. Based on long-term ethnographic feldwork among pro-Kurdish activists, she concludes that “the reasons and motives of the volunteers change throughout the engagement. People are continuously infuenced: they act and are acted upon. . . . Decisions are made along the journey.”[22]

Wartime Experiences and Military Contribution

Recent scholarship has done much to illuminate various facets of the volunteers’ wartime experiences and interactions with their hosts. Jorge Marco and Maria Thomas, for instance, explore the implications of deploying a linguistically diverse force like the International Brigades that fought in Spain. They acknowledge that “[T]he dizzying mixture of languages present in the ranks of the Republican war efort . . . created serious and sometimes dangerous communication difculties,” forcing the high command of the International Brigades to abandon its initial internationalist and utopian organizational vision.[23] A more pragmatic approach was adopted after the Battle of Jarama (February 1937), with brigade commanders reorganizing soldiers into units where diferent languages were dominant. This improved military communication but reduced linguistic diversity within individual brigades. Marco and Thomas also emphasize the importance of polyglot volunteers who, as language intermediaries, became “an indispensable element of the Republican war efort.”[24]

The military signifcance of foreign volunteers to their host’s war efort has become a hotly contested topic in recent years. Focusing on the foreigners who fought alongside anti-Russian insurgents in the First and Second Chechen War, Kristin Bakke puts forward the following notion:

Although transnational insurgents may strengthen a domestic insurgent movement by contributing resources, fghters, and know-how, they can also weaken the movement by introducing new ideas about what the struggle is about and how it should be fought.[25]

Indeed, Bakke argues that some of the ideas and tactics that the foreign fghters introduced into the confict fueled divisions within the resistance movement and caused a popular backlash among Chechen society.

For its part, the United Nations Security Council adopted a far lessnuanced view. The high number of foreigners who focked to Syria during the early years of its civil war and the emergence of the Islamic State prompted the UNSC to pass Resolution 2178 in September 2014. It deployed a new term—“foreign terrorist fghters”—which elicited scholarly criticism, and it asserted unequivocally that such “fghters increase the intensity, duration and intractability of conficts.”[26] Early analysis seemed to conform to this view. When discussing the role played by foreigners who joined the ranks of the Islamic State in Syria and Iraq, Fabrizio Coticchia argues, “[M]ilitary experience acquired in other conficts is vital in the case of ISIL” and

that foreign fghters have played a role particularly with regards to the capability to carry out specifc tactics, such as suicide bombings, to share lessons learnt on conventional warfare, and to adapt, both in the structure of training and in methods of addressing new challenges (e.g., air strikes).[27]

Conversely, my own research has shown that, across several conficts, foreign volunteers have a mixed record in terms of their military contribution. Numerically, they tend to make up a small fraction of the fghting force of their hosts, often constituting less than 10 percent. On numerous occasions, untrained and unsuitable volunteers proved to be a nuisance for the armed forces they joined. If foreigners have been of beneft to their hosts, it was in cases where the volunteers brought with them technical expertise that was otherwise lacking (e.g., the ability to fy aircraft) or where their presence conferred political and propagandistic value.[28]

A number of recent studies provide more evidence that the primary contribution of foreign volunteers to their hosts is more likely to be political rather than military. Take, for example, the almost passive-aggressive statement by Transvaal President Paul Kruger to arriving foreign volunteers during the South African War (1899–02), cited by Kennedy and Holdridge:

I thank you for coming! . . . But we did not need you. Transvaal does not need any help from the outside. But because you want to fght for us, you are welcome. I take yours as a good sign that Europe is gradually recognizing the right of the Afrikander people![29]

Naman Karl-Thomas Habtom argues that the foreign volunteers who focked to Ukraine in 2022 provided limited operational benefts for their hosts. Their main role has been outward-facing, internationalizing the confict in order to sway Western public opinion, though even this propagandistic contribution was fairly short lived.[30]

The wartime experiences of minority groups and women who volunteer in foreign conficts remain relatively understudied. There have been some pioneering studies in the context of the Spanish Civil War. For instance, Angela Jackson examines the distinctive involvement of British women in the war in Spain.[31] Gerben Zaagsma has shed new light on the Polish Jews, many of whom had resided in exile in France and Belgium before the Spanish Civil War erupted and went on to form part of the Botwin Company, a distinctly Jewish contingent within the International Brigades.[32] The present volume seeks to expand our understanding of women and minority groups in the war in Spain.

Post-Confict Return and Memory

The often-difcult post-confict trajectories of those foreigners who joined the Islamic State in Syria raises the question of what happens to transnational recruits who end up on the losing side. As recent studies have shown, the lengthy confnement of foreigners at al-Hol camp and their delayed repatriation from Syria are not without precedent. Kennedy and Holdridge have shown how Britain held foreigners who had fought for the Boers in the South African War in prisoner-of-war camps across the empire. The British authorities often denied petitions by European consular ofcers, arguing that the volunteers had lost their right to consular support by joining Boer forces, thereby violating their countries’ neutrality.[33] Robert Gildea and his associates wrote about the camps that were set up by the French government in 1938–39 along the Pyrenean frontier with Spain and in French North Africa to detain exiled Republican Spaniards and International Brigaders who were unable to return to their home states. The authors demonstrate how these camps soon became “crucibles for transnational resistance” once the Second World War broke out.[34]

The dramatic and at times cruel treatment of returnees from Syria, with some Britons being stripped of their citizenship, prompted historians to look at how ideologically suspicious volunteers who returned from Spain were treated in the late 1930s and early 1940s. Fraser Raeburn found that although the British state was wary of the supposed revolutionary tendencies of veterans returning from Spain, it did not impose substantive blanket restrictions on the activities of former International Brigade volunteers during the Second World War. There was some surveillance, but only a minority of the veterans were ever actually watched. In general, the approach of the British security apparatus was pragmatic: a sizeable portion of the Scots who returned from the Spanish Civil War were subsequently able to serve in the British armed forces, especially from 1940 onwards.[35] Jorge Marco observed how, in the United States, William J. Donovan, the frst director of what soon became known as the Ofce of Strategic Services (OSS), recruited a number of International Brigades veterans and sent them to serve as instructors in a newly established school for training in guerrilla warfare.[36] Conversely, Samuël Kruizinga, who has examined the trajectories of Dutch returnees from Spain, found that the volunteer Jef Last, among others, had his citizenship revoked in December 1936. He was allowed to re-enter the Netherlands, but as a stateless person. His citizenship was only restored in 1947.[37] David Malet and Jason Fritz, who surveyed historical responses by states to returnees, conclude that “returning foreign fghters were often left to themselves unless considered a threat to the state to which they returned.”[38]

Finally, historians have continued to explore how the memory of cohorts of foreign volunteers in specifc countries changed over time. When Sweden’s volunteers returned from Spain, they were hailed as heroes by the workers’ movement. However, soon afterwards the veterans were routinely subjected to police surveillance and harassment. A handful of veterans were interned as potential security threats during the Second World War. All this changed after 1945. Carl-Gustaf Scott notes:

[T]he Swedish Left has needed to lean on the International Brigades’ legacy more than most. For unlike the majority of its West European counterparts, the Swedish Left could not employ its role in the antiNazi resistance as a basis for its postwar legitimacy.[39] This sentimentality about the “good fght” has led to idealized depictions of the volunteers’ exploits in Spain.

Raanan Rein illustrates how the marginal group of Jewish communists who left Palestine to fght in Spain gradually made their way into the Israeli consensus some ffty years later. Although many of these volunteers had been part of the Palestine Communist Party, which was opposed to Zionism, with time their “struggle was appropriated by the Zionist establishment and they were portrayed as Jewish heroes, national patriots fghting to protect their people.”[40] As pioneers in the antifascist struggle, these volunteers in the International Brigades could be linked to the memory of the Warsaw Ghetto Uprising and other heroic fgures in Jewish history.

At times, the memory of cohorts of foreign volunteers can do more than refect the changing political and cultural landscape of their home state. Enrico Acciai focuses our attention on the enduring appeal of the Garibaldian tradition as a source of inspiration for subsequent generations of volunteers:

The capacity of war volunteering to endure and persist over time has rarely been investigated in historiography: that is, the continuation not only of memories passed down from one generation of fghters to another, but also its ability to start up again as soon as a new movement of volunteers appears.[41]

Acciai points out that the tradition of the red shirts was invoked and manifested itself in Poland (1863), Crete (1866–67), France (1870–71), the Balkans (1876), Greece (1897), Serbia (1912 and 1914), and again in France (1914–15), during the Spanish Civil War, and among resistance movements in Italy, France, and the Balkans during the Second World War. In fact, echoes of the Garibaldian tradition could still be observed among some of the foreign volunteers who joined the Kurdish YPG in their fght against the Islamic State in Syria.

Foreign volunteers clearly represent an enduring phenomenon. Their motivations, experiences, signifcance, and legacy will undoubtedly continue to attract historiographic attention in years to come. With regard to the Spanish Civil War, new sources on individual volunteers may continue to come to light, as the example of Yael Gerson, examined in this volume, illustrates. The emergence of such sources can enrich our understanding of the support networks that assisted and sustained the International Brigades. Another area where the feld is likely to expand is in the investigation of understudied historical episodes of volunteering. For instance, the project “Foreign Fighters: Past, Present and Future,” led by Morten Heiberg at the University of Copenhagen, will highlight continuities between volunteering during the antifascist struggle of 1936–45 and the early Cold War period (1945–62).[42] Another case study that is ripe for further investigation is that of the Bangladeshi, Kurdish, and other foreign volunteers who fought alongside Palestinian organizations in their war against Israel in Lebanon in 1982.[43] Finally, the integration of foreign volunteers in the Ukrainian armed forces during the current war with Russia will likely lead to new studies and, possibly, new insights that will help us to reassess the past.

Bibliography

Acciai, Encrico. Garibaldi’s Radical Legacy: Traditions of War Volunteering in Southern Europe (1861–1945). London: Routledge, 2021.

Acciai, Enrico. “L’Ucraina ha bisogno dei volontari anche se non vincerà così la Guerra.” Domani, March 17, 2022. www.editorialedomani.it/politica/mondo/ ucraina-soldati-stranieri-legione-volontari-foreign-fghters-guerra-crisi-m4adgonu.

al-Saadi, Yazan. “Remembering the Past: Bangladeshi Fighters for Palestine of the 1980s.” Pakistan Defence, October 7, 2016. https://defence.pk/pdf/threads/ remembering-the-past-bangladeshi-fghters-for-palestine-of-the-1980s.454038/.

Arielli, Nir. From Byron to bin Laden: A History of Foreign War Volunteers. Cambridge, MA: Harvard University Press, 2018.

Baker-Beall, Christopher. “The Concept of the Foreign Terrorist Fighter: An Immanent Critique.” European Journal of International Security 8, no. 1 (2023): 25–46.

Bakke, Kristin M. “Help Wanted? The Mixed Record of Foreign Fighters in Domestic Insurgencies.” International Security 38, no. 4 (2014): 150–87.

Baxell, Richard. “Myths of the International Brigades.” Bulletin of Spanish Studies 91, no. 1–2 (2014): 11–24.

Bofey, Daniel. “‘I Don’t Like Bullies’: British Volunteers Tell Why They’re Fighting for Ukraine.” The Guardian, April 2, 2022. www.theguardian.com/world/2022/ apr/02/i-dont-like-bullies-british-volunteers-tell-why-theyre-fghting-for-ukraine.

Cancian, Mark F. “Foreign Volunteers in Ukraine: Warfghters or Propaganda Tools?” CSIS, April 5, 2022. www.csis.org/analysis/foreign-volunteers-ukrainewarfghters-or-propaganda-tools.

Coticchia, Fabrizio. “The Military Impact of Foreign Fighters on the Battlefeld: The Case of the ISIL.” In Foreign Fighters under International Law and Beyond, edited by Andrea de Guttry et al., 121–38. The Hague: Springer, 2016.

Esenwein, George. “Freedom Fighters or Comintern Soldiers? Writing about the ‘Good Fight’ During the Spanish Civil War.” Civil Wars 12, no. 1–2 (2010): 156–66.

Genc, Elif. “The Kurdish Movement’s Relationship with the Palestinian Struggle.” MERIP, 2020. https://merip.org/2020/08/the-kurdish-movements-relationshipwith-the-palestinian-struggle/.

Gildea, Robert, Jorge Marco, Diego Gaspar Celaya, Milovan Pisarri, Enrico Acciai, Bojan Aleksov, and Yaacov Falkov. “Camps as Crucibles of Transnational Resistance.” In Fighters across Frontiers: Transnational Resistance in Europe, 1936–48, edited by Robert Gildea and Ismee Tames. Manchester: Manchester University Press, 2020.

Grasmeder, Elizabeth M. F. “Leaning on Legionnaires: Why Modern States Recruit Foreign Soldiers.” International Security 46, no. 1 (2021): 147–95.

Grasmeder, Elizabeth M. F. “Lessons from Finland for Ukraine and Its Foreign Legion.” War on the Rocks, March 21, 2022. https://warontherocks.com/2022/03/ lessons-from-fnland-for-ukraine-and-its-foreign-legion/.

Habtom, Naman Karl-Thomas. “The Composition and Challenges of Foreign Fighters in Ukraine.” Scandinavian Journal of Military Studies 5, no. 1 (2022): 79–90

Hall, Richard. “They Came to Syria to Fight Isis. Now They Want to Stay.” The Independent, February 25, 2019. www.independent.co.uk/news/world/middle-east/isissyria-soldiers-kurds-ypg-turkey-britain-a8793081.html.

Hazkani, Shay. Dear Palestine: A Social History of the 1948 War. Stanford: Stanford University Press, 2021.

Hopkins, James K. Into the Heart of Fire: The British in the Spanish Civil War. Stanford: Stanford University Press, 1998.

Jackson, Angela. British Women and the Spanish Civil War. London: Routledge, 2002.

Keene, Judith. “Fighting for God, for Franco and (Most of All) for Themselves: RightWing Volunteers in the Spanish Civil War.” In War Volunteering in Modern Times: From the French Revolution to the Second World War, edited by Christine G. Krüger and Sonja Levsen, 211–30. Basingstoke: Palgrave, 2011.

Kennedy, Wm. Matthew, and Chris Holdridge. “‘The Recognized Adjunct of Modern Armies’: Foreign Volunteerism and the South African War.” European Review of History 27, no. 1–2 (2020): 111–33.

Kruizinga, Samuël. “The First Resisters: Tracing Three Dutchmen from the Spanish Trenches to the Second World War, 1936–1945.” War in History 27, no. 3 (2020): 368–86.

Kruizinga, Samuël, and Miriam van der Veen. “Sketches of Spain: The Role of the Left-Wing Press in Britain, the Netherlands, and Amongst Exiled Germans in Recruiting Volunteers for Republican Spain during the Spanish Civil War, 1936– 1939.” Contemporary European History (2022): 1–17. https://doi.org/10.1017/ S0960777322000376.

Kushnir, Maryan. “Ukraine’s Foreign Legion: Soldiers Speak of Historic Fight for Democracy.” Radio Free Europe/Radio Liberty, June 17, 2022. www.rferl.org/a/ ukraine-russia-foreign-legion-american-volunteers-history/31918210.html.

Lambe, Ariel Mae, and Fraser Raeburn. “Foreign Volunteer Fighters Can Greatly Assist Ukraine. But There Will Be Challenges, Too.” Washington Post, March 10, 2022. www.washingtonpost.com/outlook/2022/03/10/foreign-volunteers-cangreatly-assist-ukraine-there-will-be-challenges-too/.

Lambert, Michael. “In Spain as in Syria, People Fight in Foreign Wars for Many Reasons, or Sometimes None at All.” The Conversation, August 4, 2016. https:// theconversation.com/in-spain-as-in-syria-people-fght-in-foreign-wars-for-manyreasons-or-sometimes-none-at-all-63469.

Li, Darryl. The Universal Enemy: Jihad, Empire, and the Challenge of Solidarity. Stanford: Stanford University Press, 2019.

Malet, David. Foreign Fighters: Transnational Identity in Civil Conficts. Oxford: Oxford University Press, 2013.

Malet, David, and Jason E. Fritz. “Historical Responses to Foreign Fighters and Returnees.” In Returning Foreign Fighters: Responses, Legal Challenges and Ways Forward, edited by Francesca Capone, Christophe Paulussen, and Rebecca MignotMahdavi. The Hague: Springer, 2023.

Marco, Jorge. “Transnational Soldiers and Guerrilla Warfare from the Spanish Civil War to the Second World War.” War in History 27, no. 3 (2020): 387–407.

Marco, Jorge, and Maria Thomas. “‘Mucho Malo for Fascisti’: Languages and Transnational Soldiers in the Spanish Civil War.” War and Society 38, no. 2 (2019): 139–61.

Petti, Matthew. “The Kurds Who Died for Palestine.” New Lines Magazine, April 27, 2023, https://newlinesmag.com/argument/the-kurds-who-died-for-palestine/.

Raeburn, Fraser. “Politics, Networks and Community: Recruitment for the International Brigades Reassessed.” Journal of Contemporary History 55, no. 4 (2020): 719–44.

Raeburn, Fraser. “The ‘Premature Anti-Fascists’? International Brigade Veterans’ Participation in the British War Efort, 1939–45.” War in History 27, no. 3 (2020): 408–32.

Rein, Raanan. “A Belated Inclusion: Jewish Volunteers in the Spanish Civil War and Their Place in the Israeli National Narrative.” Israel Studies 17, no. 1 (2012): 24–49.

Richardson, R. Dan. Comintern Army: The International Brigades and the Spanish Civil War. Lexington: The University Press of Kentucky, 1982.

Romilly, Esmond. Boadilla. London: Macdonald, 1971.

Schmutz, Timrah. “‘Lone Soldiers’ in the Israeli Military—A Research Note on the Conceptualization of Foreign Fighters.” Terrorism and Political Violence 34, no. 8 (2022): 1665–78.

Scott, Carl-Gustaf. “The Swedish Left’s Memory of the International Brigades and the Creation of an Anti-Fascist Postwar Identity.” European History Quarterly 39, no. 2 (2009): 217–40.

Thomas, Hugh. The Spanish Civil War. New York: Harper and Row, 1961.

United Nations Security Council S/RES/2178, September 24, 2014. www.un.org/ securitycouncil/s/res/2178-%282014%29.

Weinraub, Bernard. “Israelis Charge Palestinian Use of Mercenaries.” New York Times, July 11, 1982.

Weiss, Nerina. “Good Radicals? Trajectories of Pro-Kurdish Political and Militant Mobilisation to the Wars in Syria, Turkey and Iraq.” Critical Studies on Terrorism 13, no. 3 (2020): 373–95.

Yohanani, Lior. “High-Risk Transnationalism: Why Do Israeli-Americans Volunteer in the Israeli Military?” Sociological Forum 37, no. 2 (2022): 533–56.

Zaagsma, Gerben. Jewish Volunteers, the International Brigades and the Spanish Civil War. London: Bloomsbury, 2018.