I

In the Sikorski Institute and Museum in London, which houses an extensive collection of documents relating to Poland’s involvement in the Second World War, there is a striking passage in a report on the September campaign, prepared shortly after its unsuccessful conclusion:

What makes this passage particularly striking is that it does not describe a clash with a foreign adversary, but a confrontation between the soldiers and civilians of the Second Polish Republic – between the state’s army and its own population during the September campaign of 1939. This depiction of violence in the Wołyń region, on the south-eastern periphery of the interwar Polish state, raises fundamental questions about state–society relations under conditions of war. What did such brutal encounters between the military and the people it was meant to protect signify in the context of state–society relations? To what extent were they exceptional, and to what extent did they reflect pre-existing social and national divisions? Were there discernible geographical or social boundaries separating communities perceived as loyal or disloyal to the state and its army?

This article argues that encounters between the Polish army and civilians were not merely chaotic by-products of military defeat, but moments in which competing hierarchies of state, national, and social identity were exposed and renegotiated under conditions of institutional collapse.Footnote ² By tracing these interactions along the route of a single military formation, it shows that perceptions of ‘loyalty’ and ‘betrayal’ were shaped less by abstract notions of ‘national antagonism’ than by locally embedded configurations of power, memory, and social stratification.

The analysis focuses on the Independent Operational Group ‘Polesie’ (SGO Polesie) and its attached units operating in September–October 1939. Accounts from its members reconstruct civilian responses along the formation’s combat route. The SGO Polesie’s path cut across several ethnically diverse regions, providing a unique vantage point from which to observe army–civilian relations under invasion and state collapse.Footnote ³

The SGO Polesie, a corps-level formation commanded by General Franciszek Kleeberg, was mobilized in late August 1939 in the northern sector of Poland’s eastern borderlands (today western Belarus and southern Lithuania, known as Kresy Północno-Wschodnie). Initially tasked with confronting the Wehrmacht and organizing a defensive line in Polesie (now south-western Belarus), its plans were disrupted by the Soviet invasion of 17 September. Attacked from east and west, the formation withdrew into Wołyń (now north-western Ukraine) before turning west towards central Poland in a final attempt at organized resistance. As the last major Polish formation in the field, it moved in a wide arc over multiple regions, encountering populations whose attitudes towards the state and its army varied markedly.Footnote ⁴

For clarity, references to local populations – Poles, Belarusians, and Ukrainians – are based on linguistic and ethnographic markers used in contemporary sources. Nevertheless, this type of identification across the region was mostly fluid, and widespread ‘national indifference’ persisted. Thus this study interprets national identity as a situational resource, activated or muted according to shifting power relations. Modernist theories of nationalism, associated with Benedict Anderson, Eric Hobsbawm, Miroslav Hroch, and Ernest Gellner, emphasize the constructed nature of nations.Footnote ⁵ Recent case-studies by James E. Bjork, Jeremy King, Olga Linkiewicz, and Brendan Karch demonstrate the persistence of national indifference in east-central Europe in the twentieth century, while Rogers Brubaker has further deconstructed the concept of national identity itself.Footnote ⁶

A fourth segment of the local population – the Jewish community – is not treated separately, as the sources contain only limited references. Two factors probably account for this absence. First, Jewish populations were concentrated in urban centres, whereas the SGO Polesie operated almost exclusively in rural areas, with few exceptions. Second, communal separation, combined with antisemitic attitudes among some officers, meant that Jews were rarely perceived as subjects of sustained interest. Given both the evidentiary limitations of the sources and the extensive scholarship on Jewish life in interwar eastern Poland, a separate analysis falls outside the scope of this study.Footnote ⁷

In addition to contributing to studies of nationalism, this article engages broader debates on violence and state collapse. Building on Charles Tilly’s linkage of war-making and state-making and Michael Mann’s analysis of state power and ethnic cleansing, historians have explored how political disintegration reshapes the legitimacy of violence.Footnote ⁸ In the eastern European context, scholars such as Timothy Snyder, Grzegorz Motyka, and Jan T. Gross have shown how overlapping state collapses and competing national projects created local reality in which neighbours turned against one another.Footnote ⁹ By focusing on a mobile military formation in the final weeks of the Polish campaign, this article demonstrates how perceptions of state withdrawal catalysed acts of defiance, accommodation, and retribution.

The study relies primarily on archival materials produced by Polish military personnel mostly in the years after the campaign, including official and semi-official reports preserved at the Sikorski Institute and Museum, the Studium Polski Podziemnej, the Piłsudski Institute (all in London), and the Central Military Archive in Warsaw. Rather than treating these documents as neutral records, the article reads them as evidence of perception – texts through which officers articulated anxieties about loyalty, authority, and the moral cohesion of the state. Their biases, particularly towards rural communities in the culturally diverse Polish eastern borderlands, are analysed as historically meaningful responses to defeat. Although the events they describe were generally real, their interpretations reflect the authors’ subjective experiences of military collapse.

These sources do not provide direct access to civilian voices, but they illuminate how the army understood social fragmentation and its role in state disintegration. To contextualize these predominantly patriotic and pro-Polish perspectives, the study draws selectively on local oral histories and memoirs.Footnote ¹⁰ These supplementary materials serve primarily as background rather than a full reconstruction of civilian experience. Taken together, however, the sources allow for a reconstruction of intra-social relations during the crucial weeks of September 1939.

II

The first mobilization measures undertaken by the Second Polish Republic along its north-eastern borderlands began shortly after Germany’s annexation of Klaipeda on 23 March 1939. This frontier zone stretched from the Wilno region in the north to the Pripyat river in the south, an area that today lies largely in southern Lithuania, eastern Poland, and western Belarus.Footnote ¹¹ These initial measures took the form of covert military preparations, including the partial reorganization of selected units and their redeployment towards the Polish–German border in anticipation of an imminent conflict. As this was only a limited mobilization, activation remained restricted to specific formations. Many of these units were already stationed outside the north-eastern borderlands at the outbreak of war, with numerous local recruits subsequently killed or captured during combat within the Polish core territories.Footnote ¹² Although this phase lies beyond the immediate scope of the present study, it nonetheless offers valuable insight into local societal attitudes towards the Polish state – aptly described through Rok Stergard’s concept of ‘pragmatic conformity’, namely an attitude where individuals or groups comply with a dominant system not out of genuine loyalty but for practical, self-serving reasons.Footnote ¹³

As summarized in a detailed analysis by Captain Apoloniusz Kucharski, written in 1939–40 while imprisoned in a German POW camp, mobilization expectations were initially cautious:

Yet Kucharski’s report reveals that military commissions were surprised by both the efficiency of the mobilization process and the loyalty of conscripts, who reported promptly upon receiving their orders: ‘These predictions proved overly conservative – and, fortunately, inaccurate in the most crucial sense. The influx of reservists far exceeded expectations, with nearly 3,000 men streaming in between A00+10 and A00+25.’Footnote ¹⁴

For most formations relevant to this analysis, full mobilization began only in late August and early September 1939, following the official outbreak of hostilities. In these instances, conditions remained similar to those observed during the preliminary mobilization. According to Second Lieutenant of Artillery Mikołaj Hałaczkiewicz: ‘The battalion was reinforced with men from the north-western borderlands – arriving not yet as part of the general mobilization, but in response to individual call-ups. They were solid men, both physically and morally strong.’Footnote ¹⁵

Contemporary reports consistently describe local reactions as ones of ‘friendly neutrality’ – neither actively supportive nor overtly oppositional – a characterization that best captures the nature of state–society relations in the Polish north-eastern borderlands. From the military command’s perspective, the most critical outcome was that legal obligations were fulfilled.Footnote ¹⁶ Some mobilization centres were even closed early after reaching their quotas. As Captain Paweł Jan Wacławowicz recorded: ‘During the general mobilization, several hundred men reported to the regiment – but they had to be turned away. The regiment was already fully mobilized; there was neither space to house them nor uniforms to clothe them. A few days later, the same scene repeated itself.’Footnote ¹⁷ Reports from multiple units echo the same tone of efficiency: ‘The regiment was mobilized on 24 August 1939, and the process unfolded swiftly’Footnote ¹⁸ or ‘Assessing the course of these two days of war, I state that the mobilization of the army went very smoothly, the spirit of the troops was very good, and everything was done on time.’Footnote ¹⁹

A crucial factor sustaining the region’s neutral posture was the identity of its largely rural population, with approximately 90 per cent living in the countryside and only about 10 per cent in urban areas according to the 1931 census. Their self-identification was often rooted in religious or linguistic affiliation, with only a fragmentary sense of national consciousness, if any. Unsurprisingly, in the absence of a strong national identity, most local responses to mobilization were characterized by passive compliance with state expectations.Footnote ²⁰

The apparent simplicity with which local communities accepted the state’s war effort conceals a deeper historical significance. The so-called north-eastern borderlands had long resisted integration into the interwar Polish state, owing to their ethnic diversity, the legacies of Russian imperial rule – including policies designed to curtail Polish presence – and their proximity to the Soviet Union, which actively supported anti-Polish movements in the region.Footnote ²¹ In the early 1920s, immediately following the creation of the Second Polish Republic amid the collapse of three continental empires, desertion among conscripts and rural resistance to Polish administration were widespread. By 1939, however, the majority of inhabitants – having spent their formative years as citizens of the Polish state – had come to accept its authority. Even professional officers expressed surprise at this development, as Kucharski’s report underscores. Despite enduring grievances over land reform, economic neglect, and cultural marginalization, rural communities had largely adjusted to Polish rule, transforming into a society of ‘decent citizens’ willing to fulfil the state’s basic demands.

A particularly telling testimony of western Belarusian acceptance of the Polish state comes from Captain Adam Jarosiński of the 79th Infantry regiment: ‘The most resistant to the plague of desertion turned out to be my 7th company – despite, or perhaps precisely because, it consisted of a high percentage of Belarusians. … This company … did not produce deserters, and I could count on it until the end [October 1939].’Footnote ²² This sentiment – reflecting ‘imperial patriotism’, a form of loyalty among non-core communities in multi-ethnic states – is even more pronounced in the memoirs of General Władysław Anders, a leading figure in the Polish government-in-exile and the Polish Armed Forces in the West.Footnote ²³ Recalling a conversation with Joseph Stalin, Anders described how Stalin dismissively remarked: ‘What do you need Belarusians, Ukrainians, and Jews for in the army to be created from Polish POWs in the USSR? You need Poles – they make the best soldiers.’ Anders replied bluntly: ‘As for the Belarusians, they considered themselves Poles and were good soldiers during the 1939 war.’Footnote ²⁴

III

With the German offensive underway, dozens of second-line units – mostly drawn from formations already engaged on the Polish–German front – gradually converged on the southern fringes of Poland’s north-eastern borderlands, in marshy Polesie. Their presence resulted both from the general chaos of war and from organized withdrawals before the advancing Wehrmacht, as well as from the fact that several units had already been stationed in the area. In view of the scale of German successes, the Polish army’s general headquarters decided to consolidate these scattered forces into a single army group under Franciszek Kleeberg. The aim was to establish a defensive line in Polesie capable of halting the German advance and securing the rear of Polish positions.

This area – today located largely in southern Belarus, primarily within Brest Oblast – was then administered as the Polesie voivodeship.Footnote ²⁵ It was the poorest region of interwar Poland, burdened by profound infrastructural and administrative deficiencies. Historically a borderland between Belarusian and Ukrainian ethnic zones, Polesie also encompassed substantial Polish and Russian populations. In the interwar period, the inhabitants of the region were often described neither as Belarusians nor as Ukrainians but as Poleshuks or simply Tutejsi – terms that reflected the area’s distinct cultural and social characteristics. To outside observers, however, these characteristics were frequently interpreted as signs of backwardness.Footnote ²⁶ This perspective is captured in a 1937 pamphlet published by the Eastern Lands Development Society, which described Polesie as follows: ‘The Polesie Voivodeship, territorially the largest of all voivodeships, covering an area of 36,867 km² and accounting for 10% of Poland’s territory, is – in terms of economic and cultural development – the most underdeveloped and backward voivodeship.’Footnote ²⁷

Despite the early presence of pro-communist elements in Polesie – more visible than on the northern frontier – soldiers’ memoirs and reports suggest that the local population initially remained ambivalent towards the Polish army. Civilians generally provided intelligence and other assistance when requested, but rarely displayed patriotic fervour, which appear to have been largely absent beyond the relatively rare instances observed in larger towns across the region.

Among the population, a general tendency towards accepting any ruling power seems to have dominated. Notably, locals continued to submit requests for the release of conscripted family members for agricultural work even as the Polish state collapsed – underscoring their continued engagement with its administrative structures.Footnote ²⁸ These petitions, often tied to harvest needs, illustrate the pragmatic mindset of a population primarily concerned with local matters – a perspective rooted in the tradition from the era when the defence of state borders was largely irrelevant to the daily lives of the peasantry. As a result, the war was mainly perceived by local peasants as external to their own concerns and, unless it directly affected them, as generally unimportant. Soldiers’ memoirs often describe indifference among the population, even in the midst of violent conflict.Footnote ²⁹ One example comes from Lieutenant Piotr Szymonis, who recalled an encounter with the local continuation of normal life during a rapid march following a bloody battle with the Germans: ‘After a few kilometres of a breakneck ride, I pulled a sleepy Poleshuk out of his cottage and ordered him to lead the way. This is how I made it to Jamnik.’Footnote ³⁰

The mentioned lack of interest of the local population in the ongoing conflict may also have been influenced by mobilization, the result of which was that the most patriotic individuals in terms of state affiliation were removed from their communities. As noted in a report from the IX Corps District Command, during the very early stage of mobilization: ‘In Pińsk County, in some localities, only reservists of the Roman Catholic faith received draft cards. This fact caused discontent among the Orthodox population, who demanded that not only “Poles” be called up, since they too wanted to fight for Poland.’Footnote ³¹

This divide between loyalists, the ambivalent, and opponents of the state became especially evident during the Battle of Kobryń, which coincided with a pivotal moment in the campaign: the onset of Soviet aggression on 17 September. The first German attack on the town was launched on 14 September, with the general assault occurring on 17–18 September. Despite heavy fighting, the Polish army managed to withstand the German blow and hold the area. However, following news of the Soviet advance from the east, the Polish command decided to abandon the town and retreat south, anticipating inevitable defeat in the face of a two-pronged attack. This decision aligned with the order of the Polish commander-in-chief for troops to move towards Romania or Hungary, which were intended as sanctuaries for regrouping the army and continuing the fight on the western front.

The Germans occupied Kobryń on the night of 18 September, only to transfer the town to Soviet control four days later, in accordance with the Molotov–Ribbentrop Pact, which divided Poland – and much of eastern Europe – into spheres of influence between the two regimes. In this way, the pact temporarily united two ideologically opposed powers.

During the battle, parts of the local community provided support to the Polish army, memory of which remains in the local history: scouts helped military units, women’s organizations cared for the wounded, and local men took part in the city’s defence. Fourteen-year-old Helena Arciszewska recalled:

Such actions in support of the army may be interpreted as grassroots expressions of a segment of the local population’s Polish national and political identification, as well as a willingness to assume risk and make sacrifices even under extreme conditions.

Simultaneously, these events revealed the existence of antagonistic groups within the same territory: individuals from marginalized communities who used the moment to settle scores with their oppressors. This antagonism escalated dramatically after the Soviet Union entered the war on 17 September 1939. The actions of the girl scouts described above were accompanied by directly contrasting ones. Colonel Adam Epler, who commanded the defence of Kobryń, left the following note in his 1940 report:

In this description, the colonel seems to be referring to the emergence of a local revolutionary committee (revkoms), which spread across the entire region as a result of communist underground activity. He mistakenly interpreted the German tolerance for its formation as active participation in its establishment. While his recollections, due to the rapid unfolding of events and his incomplete understanding, contain factual errors in interpretation, they still provide an important record of the local pro-Soviet activists’ response to the collapse of the Polish state.

Thus the Soviet invasion activated communist underground cells that began targeting Polish forces. Lieutenant Commander Franciszek Korczyński clearly underlines this event as a turning point that radically changed the nature of the population–army relations:

There are recorded accounts from after 17 September that indicate the involvement of the local anti-Polish activists in attacks on members of the SGO Polesie in the Kobryń area. Similar incidents probably occurred elsewhere in the region, wherever groups of locals perceived themselves as oppressed by the Polish state. As noted by two witnesses of the events, P. P. Rybchuk and N. A. Prokopchik (whose full names are unfortunately unavailable), in conversation with the local historian Nina G. Marchuk: ‘At that time [after 17 September], the forests were teeming with gangs of various criminals and Ukrainian nationalists who hated Poland and sympathized with the Soviet–Fascist allies.’Footnote ³⁵

This outcome is not surprising as, during the interwar years, Polesie had been a hub of clandestine anti-state activity, driven by the region’s persistent economic and social problems. With the collapse of the Polish state and the arrival of the Red Army, well-organized saboteurs and Soviet sympathizers began asserting influence, particularly in the more remote areas of the region. In towns and villages, revolutionary committees sought to fill the emerging power vacuum. This dynamic, coupled with the local population’s responses, understandably heightened the concerns of the military, which had long maintained a cautious or reserved attitude towards the rural populace.

A vivid illustration of this growing unease can be found in the memoir of Lieutenant Stanisław Pola, who was stationed in Drohiczyn at the time of the Soviet aggression:

Pola’s account captures the complex intersection of military urgency and a community enmeshed in its own rumours, fears, and shifting loyalties, while simultaneously highlighting the condescending attitude of many elites towards the local population, which they perceived not as members of their own community but as outsiders – ‘loud, sharp-tongued’ folk.

However, despite the anti-Polish campaign of local activists, the broader population – at least initially – remained largely passive, with limited direct participation in such efforts. As Bolesław Górski, a Polish cadet who was an eyewitness to the execution of Polish officers in the village of Podziemienie near Kobryń by the members of the communist underground, described, the local population condemned the violence of the self-organized gangs. However, ‘the samogon-soaked, anarchy-hungry bandits, armed to the teeth’, were impossible to oppose, especially since their actions were also directed towards their immediate neighbours of the same ethnic and social background, the Poleshuks, Belarusians, and Ukrainians.Footnote ³⁷ Over time, as communist underground activity intensified in the context of ongoing Soviet aggression, the situation escalated further, reflecting dynamics known from the Russian Revolution.

By 20 September, when most of the Polish formations reached the Pripyat river (the southern border of the Polesie region), Polish forces increasingly viewed Polesie as hostile territory. Reserve Corporal Wiktor Lisicki of the 21st Infantry regiment wrote:

The scale of anti-Polish sentiment among the broader population remains difficult to assess, as the available sources often offer sharply conflicting portrayals of events. Moreover, many accounts are heavily shaped by the personal attitudes of their authors, who frequently interpret events in ways that reinforce their own worldview and reflect their relationships with particular ethnic groups. However, it is possible to discern the extreme patchwork of the Polesie population’s attitudes towards the Polish state. The ‘communized communities’, which actively participated in anti-state activities, were often neighboured by those who were loyal or at least neutral. General Wilhelm Orlik-Rückemann clearly noted this in a March 1940 report: ‘Along with the KOP [the Polish border guard] command, numerous families … were evacuated [from Pińsk] to Dawidgródek. … I wanted to protect the families from falling into the hands of the peasantry, who already on the first day … were clearly revealing their Bolshevik sympathies.’Footnote ³⁹ As the general’s report makes clear, moving potential victims from one town to another – located only a dozen kilo-metres away – helped ensure their safety: ‘This goal [protection from the violence] was fortunately achieved in full.’Footnote ⁴⁰

Moreover, it is important to note that the rising wave of violence had not only an institutional dimension but also an intra-social one. Acts of physical abuse were directed not just at officials but also at formally civilian individuals, both from the local population and from the influx of ‘strangers’ who had flooded the region due to the ongoing conflict and were identified with the current regime. Importantly, in this context, the violence can be mostly interpreted as socially motivated, provoked by feelings of inequality, rather than being strictly ethnically driven. An additional key indication of these events comes from local oral traditions and first-person accounts, such as the records of Bolesław Górski, P. P. Rybchuk, and N. A. Prokopchik, which often emphasize the disconnect between the perpetrators of violence and the broader population.Footnote ⁴¹ In Polesie, violence is remembered as the work of outcasts – ‘pariahs’, criminals, or profiteers – loosely affiliated with the communist underground, but ultimately disconnected from the village communities.

Available sources show a clear pattern of growing hostility towards the army among the Poleshuks, closely linked to the army’s southward movement: the further south the SGO Polesie advanced, the stronger the resistance. Three factors shaped this shift. The first was demographics: northern Polesie had significant Polish and Belarusian populations, whereas the south saw a growing Ukrainian presence, many of whom declared Ukrainian nationality in official censuses.Footnote ⁴² The second was economic development: the southern marshlands, centred around the modern Belarus–Ukraine frontier, and eastern areas near the former Polish–Soviet border, were poorly connected, with nearly impassable terrain and weak infrastructure, while the north had better infrastructure and stronger market ties. The final factor was time: after 17 September, when the Soviet Union joined Nazi Germany in invading the Second Polish Republic, the communist underground – long active during the interwar period – was empowered to mobilize, targeting so-called class enemies, who in the local context were largely identified with the Polish state and its army.

IV

As Polish formations advanced south into Wołyń (now north-western Ukraine, then part of Poland’s south-eastern borderlands), dominated by a Ukrainian majority and a politically active intelligentsia, local responses shifted sharply, culminating in large-scale armed confrontations.Footnote ⁴³ In contrast to the relative indifference or passive neutrality observed in Belarusian- and Poleshuk-inhabited areas, Polish forces in Ukrainian-majority territories faced overt hostility and organized resistance from significant segments of the local population.Footnote ⁴⁴ At least, this was the perception of reality among the Polish officer corps, which repeated the very same motive of endless clashes with the local population.

Unsurprisingly, in a 4 March 1940 report to the Polish army’s General Command in Paris, Colonel Epler described the situation in Wołyń during the army march as a ‘peasant uprising’:

This stark contrast in attitude towards the Polish army between Wołyń and Polesie is well captured in Captain Adam Jarosiński’s report:

As existing accounts suggest, hostility towards the Polish army in Wołyń was widespread. Many locals expressed their disdain for Polish troops through both passive non-cooperation and active support for Soviet or nationalist organizations. According to numerous first-hand reports created by the members of the SGO Polesie, the Polish army’s advance through Wołyń increasingly resembled a continuous series of skirmishes, with military units compelled to defend themselves against residents in nearly every village they passed. This pattern points to the fact that a significant portion of the region’s peasantry viewed the collapse of the Polish state as an opportunity to settle grievances against everything associated with their perceived oppression, framed in terms of allegiance to the Polish state.

Second Lieutenant Mikołaj Hałaczkiewicz described one such encounter:

Especially significant to this study is that some of the acts of resistance occurred before the Soviet invasion, initiated not by communists but by Ukrainian nationalists.Footnote ⁴⁸ Second Lieutenant Zygmunt Kotarski, of the 27th Regiment of Lancers, described a violent clash that likely took place between 12 and 15 September:

This scenario sharply contrasts with events on the Polish–Belarusian frontier, where sabotage and hostility largely followed the Soviet invasion and were carried out by communist underground cells rather than the broader population.Footnote ⁵⁰

As Polish units advanced south from Polesie, it became evident that local communities viewed the Polish state as an adversary. The army recognized this hostility, which shaped operational decisions.Footnote ⁵¹ Kotarski recorded a clear order: ‘After crossing the Pripyat, I received orders to scout the Krymno–Lubochiny–Nudyzhe–Luboml road and determine whether it was free of enemy forces. I was instructed to avoid villages and settlements along the way, as the local Belarusian and Ukrainian population had proven openly hostile.’Footnote ⁵² Ultimately, violence by the Polish army against ethnic Ukrainians resulted in the deaths of 996 civilians across eastern Poland, concentrated primarily in what is now western Ukraine, including Wołyń.Footnote ⁵³

Thus the Pripyat river (now part of the Belarus–Ukraine border) served as both a geographic and symbolic boundary, separating the relatively passive Belarusian north from the politically mobilized, Ukrainian-dominated south.Footnote ⁵⁴ Despite ethno-cultural proximity, the two regions reflected contrasting social realities: northern communities focused on subsistence and showed weak national consciousness, whereas southern populations embraced modern forms of identification and were prepared to actively defend the interests of their imagined community.

What is most important, however, is the difference in attitudes towards the willingness to use ethnically oriented violence on both sides of the river. This divide follows an administrative border that, although not having been officially recognized for more than a hundred years at the time, had existed since the second half of the sixteenth century, when this area became the dividing line between two parts of the Polish-Lithuanian Commonwealth.Footnote ⁵⁵

Perhaps the most harrowing testimonies from Wołyń concern the breakdown of interethnic co-existence, which within a few years would culminate in the ethnically targeted violence now known as the massacres of Poles in Volhynia and eastern Galicia. Colonel Epler described the beginning of the collapse of Polish settler life as follows:

As accounts affiliated with the SGO Polesie suggest, two related yet distinct patterns of violence emerged in Wołyń. First, organized hostilities targeted Polish military units, which were composed of conscripts from the north and west – outsiders with no connection to the region. Second, ethnic violence was directed at local civilians of Polish origin.Footnote ⁵⁷ This violence may be treated in terms of long-standing political grievances and the suppressed aspirations of segments of the local population. The collapse of Polish administration provided the most active representatives of these aspirations – Ukrainian nationalist groups – with an opportunity to assert local dominance, often through brutal means. The Polish military thus stood as both witness to and target of a rising tide of ethnic conflict.Footnote ⁵⁸ Modern academic estimates suggest that between 2,000 and 3,000 Poles were killed across the region during the events described, though such numbers remain rough and unverified as they are based on very fragmentary records.Footnote ⁵⁹

Regardless of its scale – which, during the September campaign, can scarcely be compared to the later full-scale ethnic cleansing – the violence was widely perceived as inevitable, a belief entrenched well before the outbreak of war. This became particularly clear from recollections such as those of Kazimiera Bałysz, a schoolteacher from northern Wołyń:

Such testimony suggests that expectations of interethnic conflict pre-dated the hostilities, a perception grounded in reality: segments of the Ukrainian nationalist movement had long framed the struggle in terms of creating a Ukrainian ethno-national state.

Despite the Polish army’s unquestionable tactical superiority and ability to repel most resistance, the hostility of the local population undermined its morale and strategic flexibility. Ultimately, the leadership of the army group, lacking communication with higher command, and aware of the Red Army advancement throughout eastern Poland, abandoned plans to move south towards Romania. Instead, they redirected their march westwards towards Warsaw, continuing to resist but increasingly encircled by the advancing Wehrmacht.

V

Upon crossing the loosely defined boundary commonly associated with the Curzon Line – which today roughly marks Poland’s eastern border and historically separated core Polish territories from the eastern borderlands – Polish military formations encountered a marked shift in civilian attitudes.Footnote ⁶¹ Tadeusz Śmiegielski of the 79th Infantry regiment described the experience as follows:

This contrast was all the more striking given the broader context: by this stage, the collapse of the Polish military was evident to all. Yet, despite the circumstances, the population west of the Bug displayed a clear patriotic sentiment and a pronounced willingness to support retreating Polish forces, which was noted with obvious pleasure by the members of the battle group. In stark contrast to the indifference, hostility, and violence faced in the east, the army now found itself in an environment devoid of sabotage or defiance. This transformation nevertheless posed new threats. The issue of desertion of soldiers of Polish origin now arose in a number of formations. Previously kept in the ranks by fear of the local population, they seized the opportunity to leave the army.Footnote ⁶³

Nonetheless, the issue of desertion receded in importance in the face of being in a territory whose inhabitants identified closely with the army, seeing it as their protector. As Second Lieutenant Stanisław Pola recalled:

In the vast majority of available records, the Bug river (which today forms Poland’s eastern border) emerges as a symbolic boundary separating two irreconcilable worlds: to the east, a territory marked by passive or active resistance to Polish authority; to the west, a homeland of patriotic loyalty and support.Footnote ⁶⁵ Lieutenant Korczyński offered a simple yet powerful interpretation of this transition: ‘After crossing the Bug river, sabotage activity decreased and was hardly encountered any more.’Footnote ⁶⁶ According to this view, the retreat – once marked by anxiety, danger, and disorientation – transformed almost instantly into a symbolic homecoming, marked by enthusiastic public support.

This transformation, vividly recorded by the army members, manifested not only in the absence of hostility but also in an declared eagerness to co-operate, especially among representatives of the local elite. Polish officers were welcomed into manor houses and parsonages, where members of the landed class, intelligentsia, and clergy extended solidarity, even as the state disintegrated:

Such expressions of support, particularly under conditions of military defeat and impending occupation, may be treated as a reflection of the pro-state attitude of the local population, even if SGO Polesie records undoubtedly significantly exaggerate them. From a purely pragmatic perspective, siding with a collapsing military force offered little benefit and considerable risk. Yet the persistence of such loyalty points to an enduring emotional and civic connection with the Polish state.

Another key marker of this transformation was the treatment of non-combatants accompanying military units. After a march through Wołyń, Polish forces were able to entrust local civilians with the care of vulnerable groups: wounded soldiers and officers, and Polish civilians fleeing territories with significant Ukrainian presence. This gesture signalled not only practical necessity but also trust in the loyalty and reliability of the local population:

This experience suggests that the Bug river marked not just a geographical boundary but a socio-political divide. East of the river, communities were more likely to show ambivalence or hostility towards Polish statehood; west of it, loyalty remained resilient even amid collapse. This divide cannot be explained solely by ethnicity or socio-economic factors, as Ukrainian communities and peasant grievances existed on both sides.Footnote ⁷⁰ The decisive factor appears to be patterns of state loyalty shaped largely by local elites: in the east, nationalist and communist leaders portrayed the Polish state as alien and oppressive; in the west, elites fostered a sense of Polish national belonging, largely suppressing alternative allegiances.

The reasons behind such differences are highly debatable. Nevertheless, an important factor to consider is the role of the Bug (along with the already mentioned Pripyat) as a phantom boundary.Footnote ⁷¹ For more than a hundred years after the Congress of Vienna, the Bug river was used to separate the territories of the Russian-subjugated Congress kingdom of Poland from the lands directly integrated into the Russian empire. Despite periodic efforts by the tsarist authorities to fully integrate the kingdom into the empire, divergent attitudes towards Polish statehood developed on both banks of the river during the nineteenth century, shaped by varying degrees of local autonomy and policies towards Polish language, culture, and identity.Footnote ⁷²

Importantly, while the combat group members’ accounts of the local population’s reactions reflect subjective interpretations heavily shaped by traumatic experience, more objective indicators of a different attitude towards the army are also evident. These include the complete absence of violence directed at soldiers and officers, as well as the lack of any widespread anti-state activities, whether social or political. Thus, even with a sceptical reading of the sources, the significant difference in attitudes towards the state among populations on either side of the river remains undeniable.

In essence, the Bug river divided not just regions but imagined communities – and, crucially, the national projects they embraced were mutually antagonistic.Footnote ⁷³ This contrast highlights a critical shortcoming of the Second Polish Republic’s integration strategy: it failed to cultivate a cohesive national identity. Instead, it presided over a fragmented society where regional loyalties diverged not only along ethnic or geographic lines but also according to differing perceptions of inclusion, exclusion, and political legitimacy.Footnote ⁷⁴

VI

The events of 1939 in Poland’s eastern borderlands – territories that now lie in western Belarus, Ukraine, eastern Poland, and southern Lithuania – particularly the interactions between civilians and members of the SGO Polesie, provide critical insight into the identity dynamics of the region’s diverse ethnic communities and their impact on local society. War served as a catalyst, exposing long-standing tensions and deep-rooted sentiments that had previously remained dormant. These differences became especially evident in how local communities perceived and responded to the Polish state and, above all, to its military – an institution that, for many, embodied Polish authority.

In September 1939, the Polish army encountered sharply divergent reactions from different populations: it was embraced by most Poles as a last line of defence, but met with cautious neutrality by Belarusians, reserved indifference from the Poleshuks, and open hostility from segments of the Ukrainian population. These attitudes reflected deeply ingrained group identities. Among Poles and Ukrainians, national consciousness – although directed towards opposing and incompatible national projects – shaped behaviour and fostered inevitable reactions.Footnote ⁷⁵ For Belarusians and Poleshuks, who remained largely disengaged from nationalist ideologies, attitudes were shaped instead by pragmatism and a historical tendency to acquiesce to whichever authority was dominant. Thus only among the Polish population did national and state identities coincide fully – resulting in loyalty to the Second Polish Republic, even in the face of its military collapse.

Additionally, local social dynamics played a decisive role as issues of nationalism were often of secondary importance to the local peasantry. Feelings of social inferiority and exclusion – rooted not in modern nationalism but in enduring traditional hierarchies dating back to the agrarian era – shaped popular responses to the Polish state.Footnote ⁷⁶ Among rural populations, deep-seated resentment towards landowners, elites, and the state apparatus – all of them associated with declarations of oppression – created fertile ground for intersocial animosity.Footnote ⁷⁷ While Polish identity mostly absorbed class tensions through a unifying national narrative, the situation among eastern Slavs was significantly different. The lack of any strong national identity in the case of Belarusians and Poleshuks, as well as the presence of a hostile national identity towards the Polish national project among Ukrainians, created ideal conditions for hostility to the state.

These contrasting forms of social belonging – ethnic, political, and social – which have been identified and critically interpretated by Charles Tilly, did not merely structure patterns of mobilization in September 1939; they shaped the trajectory of wartime violence and left enduring marks on post-war identities.Footnote ⁷⁸ The patterns of behaviour revealed in September 1939 largely endured throughout the war, intensifying as the political order of the interwar years disintegrated. In Wołyń, ethnic cleansing against Poles – carried out by their Ukrainian neighbours – became a defining feature of wartime atrocities, culminating in between 50,000 and 120,000 civilian victims of violence.Footnote ⁷⁹ In contrast, in western Belarus as well as eastern Poland, violence tended to be socially rather than ethnically motivated and was never on the same scale.

Despite its complexities and internal contradictions, this case-study offers a valuable framework for analysing not only how civilian populations relate to military institutions during crises but also how deeper layers of identity and belonging shape behaviour in contested spaces. Situated within what Timothy Snyder has famously termed the ‘Bloodlands’ – a zone of extraordinary violence, shifting allegiances, and enduring trauma – the events of 1939 in the Polish eastern borderlands exemplify how fragile loyalties and layered identities could determine reality during a time of political turbulence.Footnote ⁸⁰