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Encyclopedia of Invasions & Conquests, Fourth Edition

Eastern Europe, Soviet Occupation Of

In August 1939, Germany and the Soviet Union signed a non-aggression pact. The Polish government had hoped that if the Germans invaded their country the Soviets would come to their aid, since Soviet leader Joseph Stalin hated the Nazis nearly as much as Adolph Hitler hated Communists. The agreement certainly worried the Poles, but they were very surprised when two weeks after the Nazis invaded from the west the Soviets invaded from the east. No one knew of the secret part of the non-aggression pact in which the two countries decided to split Poland between them, giving each a buffer zone. Stalin apparently believed Hitler would uphold the pact, right up until June 1941 when the Nazis invaded the Soviet Union. The fast-moving “blitzkrieg” tactics caught the Soviets completely by surprise and they lost massive amounts of land and soldiers in the first six months of the offensive. When the Nazis were ultimately halted at Leningrad in the north, Moscow in the center, and Stalingrad in the south, the Soviets began their counteroffensive. Their goal was not merely to defend their country by defeating the Nazis, but to spread Communism by occupying as much of eastern Europe as possible. Starting in the spring of 1944 the drive west began.

Poland

“After the joint invasion of Poland, the two allies cooperated closely for nearly two years. Both Germany and the Soviet Union manifested equally hostile attitudes towards the Poles. It included mass killings, the annihilation of Polish elites and the extermination of Poles in concentration camps, often after having exploited them through forced labour. The Soviets methodically deported the Polish populace into forced exile in distant parts of the USSR” (Wotek, “A Post-War War”). During Nazi occupation, two underground resistance groups operated against them: the nationalist Polish Underground State and the Communist People’s Army and the People’s Guard. Rather than work together against the Nazis, the Communist groups spent more time killing members of the Underground State. When the Soviets began pushing the Nazis out of their country, the battle lines entered Poland in the summer of 1944. By this point the Polish underground had begun to coalesce into the Home Army, some 300,000 strong, with the ultranationalists and Communists then on the fringes. Further, the Soviets had organized some of the prisoners they had captured in the 1939 invasion into Polish 1st Corps with mainly Soviet officers, since many of the captured officers had been killed. This unit was ultimately part of the Belorussian Front, the rest of which consisted of twelve Soviet armies.

The Soviets attacked Poland from two directions. The northern assault known as Operation Bagration aimed at clearing Belorussia and eastern Poland; the southern assault came from Ukraine and aimed at regaining all of that province and driving westward along the Polish-Romanian border. The northern offensive started on 13 July 1944, forcing a Nazi withdrawal and gaining twenty kilometers. The southern offensive started the next day and got off to a good start, leaving the German XIII Army Corps dangerously exposed in a salient at the town of Brody. A wing of the northern offensive turned south to encircle them and by the 18th had captured the town of Kamionka Strumilowa and some bridges across the southern Bug River, cutting off the XIII Corps. By midnight on the 22nd the “Brody Cauldron” was overrun with scattered Nazi units fleeing in the night. On the 29th the Soviets reached the Vistula River, leading to a number of unsuccessful Nazi counterattacks over the next two weeks.

In the north, the Belorussian advance made good headway as well, approaching Warsaw in late August. The Polish Home Army planned to stage multiple attacks on the Germans in various cities in cooperation with the Soviet advance. On 1 September they began their moves, the most famous of which was the Warsaw Uprising. Unfortunately for the Poles, the Soviet advance did not coordinate as they promised and the Nazis were able to bloodily suppress the resistance in Warsaw and other cities. As that attempt was failing, the Soviets renewed their advance on the northern front with the aim of destroying not just the Nazis but the Polish Home Army:

The NKVD used the intelligence that the communist partisans had gathered to target members of the Polish resistance movement. It was aimed at a total liquidation of those who had confronted the Germans in the struggle for Poland’s independence. For the USSR, they were a major threat to the advancement of communist ideology and to the final conquest of Poland, because of their great attachment to the Polish state and national values as well as to the idea of freedom in general. (Wotek)

The Soviet advance in the north soon controlled northern Poland, Soviet leader Stalin ordered General Georgy Zhukov to swing south to capture Warsaw. Nazi resistance by this time was fading and the city was taken on 17 January 1945 with little fighting. During the Nazi occupation the city’s population had fallen from 1.3 million to 150,000. Two days after capturing Warsaw Zhukov’s army moving west captured the city of Lodz. The Soviets advanced on a 400-mile wide front in January and within days had driven 100 miles to reach the border of the German state of Silesia. For all intents and purposes, the German occupation of Poland was over.

For the Poles this was no blessing. “The liberation of Poland by the Soviet Union was a repeat of the 1939 conquest. The Soviets once again looted all they could from Poland, and the people starved. As the Western Allies turned a blind eye to the Soviet treatment of Poland, the [Home Army] fell apart without western support. The Polish border was redrawn as Stalin pleased. Eastern Poland, conquered by the Soviets during the 1939 invasion, was annexed” (Chen, “Poland”).

Romania

In the wake of World War I Romania had been able to take advantage of weak neighbors and expand its borders. Looking at the map, Nazi Germany saw Romania as a potentially great ally, since it had an extended border with the Soviet Union and access to the Black Sea as well as a massive oil refinery at Ploesti. Hitler tried to woo Romania into an alliance but without luck; they were happy as they were and did not see any reason to upset the countries they had acquired territories from, as those nations had grown stronger in the 1930s. Hitler used that for leverage by supporting plans to pressure Romania into giving returning all that territory. He gave support to Bulgaria, which had lost territory after the Second Balkan War in 1913; he gave support to Hungary to regain Transylvania; and “Moscow wasn’t about to let the loss of Bessarabia slide-- the territory had been with the Russians since 1812, with the Romanians later seizing upon the chaos of the Russian Civil War in 1918 in order to take it” (Egorov, “How and Why Romanians Fought”). With a weak military Romania could not resist the threats of German-supported attacks, so they had little choice but to cede most of the Bulgarian and Hungarian lands.

In their weakened state, Romania had little choice but to cooperate with Hitler when he promised them a large chunk of Ukrainian land in return for an alliance against the Soviets. The weak and poorly trained Romanian Army was included with the Nazi forces invading Russia in June 1941, and the blitzkrieg gathered lots of territories which Hitler conferred on Romania, including all of Bessarabia and much of Ukraine. In return, they contributed to the Holocaust by killing Jews and later rounding them up for concentration camps. The Romanian troops marched forward with the Nazis to the city of Stalingrad, where most of them died. As the Germans began being pushed out of the Soviet Union and losing the territory they had gained, Romanians began an anti-Nazi movement. The government leader Ion Antonescu was overthrown on 23 August 1944 by King Mihai I and immediately declared an end to hostilities with the Allies; the Red Army forces were welcomed into the capital city of Bucharest on 31 August. On 23 September the two nations signed an armistice and Romania agreed to provide twelve infantry divisions to support the Soviet offensive toward Germany.

Map by Alex:D, via Wikimedia Commons.

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Antonescu was executed as a war criminal in May 1946. King Mihai was allowed to continue his reign until the end of 1947, when a newly formed Communist government forced his abdication. The Socialist Republic of Romania was officially established.

Bulgaria

At the outbreak of World War II Bulgaria declared itself neutral, but that quickly changed with the Nazi-Soviet pact and the invasion and partition of Poland. Bulgaria’s Tsar Boris appointed a pro-German, Bogdan Filov, as leader of a new government and this slowly brought the country more into Germany’s orbit. On 1 March 1941, Bulgaria signed into the Tripartite Pact and after the invasion of the Soviet Union and the bombing of Pearl Harbor they officially declared war on Great Britain and the United States. At the time that was purely symbolic, but it would cost them later. Tsar Boris also refused to declare war on the Soviets, given that the majority of his people favored them. In the meantime, Bulgaria became a base for Nazi offensives further into the Balkans. In return, they were rewarded with possession of part of Serbia, Greek Thrace, and Yugoslav Macedonia.

Things began to change in 1943. Although Bulgarian troops were not committed to any combat, Allied air forces began bombing rail lines and industrial centers, since Germany was Bulgaria’s primary economic partner. Also, a pro-Communist faction began an underground movement after the invasion of Russia. They joined with other resistance groups to form the Fatherland Front in August.

As the war began to turn against the Nazis, many in Bulgaria expected the government to sever relations. Hitler invited Tsar Boris to Berchtesgaden where, after a hostile confrontation, Boris had a heart attack and died. As his son and heir was only six years old, Prime Minister Filov on 9 September 1943 named himself regent and appointed Dobri Bozhilov as his replacement. Although supposedly pro-German, he began seeking out contacts with the Allies. He had hoped the Allies would invade the Balkans, but the Normandy invasion in June 1944 quashed that. Filov removed Bozhilov from office on 1 June and replaced him with Ivan Bagryanov. With Soviet troops approaching Bagryanov could not handle the complicated foreign relations and he was replaced on 2 September 1944 by Konstantin Muraviev. Three days later the Soviets reached the Bulgarian border and declared war. Muraviev declared his country neutral but the Soviets would not accept that. The Fatherland Front moved to stage a coup. Even though Muraviev declared war on Germany on 8 September, that was not enough for the Communists. Kimon Georgiev overthrew the government the next day and immediately sought a cease-fire with the Soviets.

After that, any attempt to install a democratic government was impossible. “The consolidation of communist power in Bulgaria was carried out by 1948, coinciding with the completion of the peace treaty with the Allies and the presence of Soviet occupation forces. In the coalition Fatherland Front government, the communists had control of the interior and judicial ministries, which were crucial in setting up the new state” (Bell, “Bulgaria World War II”).

Czechoslovakia

The Nazi occupation of Czechoslovakia in late 1938 through early 1939 resulted in many citizens and government officials fleeing the country. President Edvard Beneš went to Britain where he was ultimately recognized as the head of a government-in-exile; many Czechs served in the French army and the British air force. At home, partisan movements formed quickly formed to resist the implementation of the “Final Solution,” which deported tens of thousands of citizens to labor or concentration camps. The units were small and generally uncoordinated, but did act bravely. In one of the major resistance actions of the war the Nazi “Protector” Reinhard Heydrich was killed by one of these groups. The cruel backlash was widespread and effective. “The terror reached its height with the annihilation of the village of Lidice, where 339 men were executed and the women and children of the village were sent to concentration camps. . . . By the time this terror--known as the ‘Heydrichiada’--was over, the Nazis had damaged the resistance movement so much that it was only able to resume its activities at the very end of the war” (GlobalSecurity, “Czechoslovakia in World War II”). President Beneš, realizing that the Soviet Union was setting itself up for postwar expansion, decided to sign an alliance treaty with them in December 1943.

Partition of Czechoslovakia, 1938-1939. Map via encyclopedia.ushmm.org.

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There was one major uprising against the Nazis in August of 1944. This movement gained more support from the Soviets than the concurrent Warsaw Uprising, but Soviet troops were not able to get into Slovakia in time and the Germans crushed it by the end of October. Still, it was just a matter of time before the drive through Poland would reach Slovakia. In March 1945, President Beneš went to Moscow to sign an accord which would help in postwar reconstruction. On 3 April a provisional government was established with Communist sympathizer Zdeněk Fierlinger installed as prime minister.

A final uprising against the Nazi occupation came in Prague on 5 May 1945, as American forces were ninety miles away to the west and the Soviet army was reaching the eastern border of Moravia. American General George Patton asked to liberate Prague but was overruled. The Yalta Agreement between Roosevelt, Churchill, and Stalin had given the Soviets the right to liberate Moravia and Bohemia. Fighting continued through 12 May, even though Germany had officially surrendered on the 8th. “The Red Army clashed in battle with the last fanatical German divisions. It was not until May 12, 1945 when the fight was completely over in the Czech Lands. The Czechs genuinely felt gratitude towards the Soviet soldiers. Czechoslovakia was mostly liberated by the Soviet Union, but western Bohemia was freed by the U.S. Army. People did not know that they became the victims in rival politics” (GlobalSecurity).

After the war, anti-Axis hostility was such that ethnic Germans and Hungarians were deported from Czechoslovakia, “and as a result about 1,600,000 ethnic Germans were deported to the American-occupied zone of Germany and about 750,000 to the Soviet-occupied zone. Somewhere between 20,000 to 250,000 ethnic Germans died during this period, most from starvation and illness, but there were reports of many murders and suicides” (Chen, “Czechoslovakia”).

Yugoslavia

The nation of Yugoslavia was formed at the Versailles Conference after World War I. The region, made up of a mixture of various Slavic peoples, had been discussing during the war how to put a nation together. In 1919, the Kingdom of Serbs, Croats, and Slovenes was created but interethnic priorities made the process very difficult. The kingdom was dominated by Serbs for ten years before King Aleksander I dissolved the parliament and created a royal dictatorship. At this point the country was renamed Yugoslavia, meaning Land of the South Slavs. This did little to suppress rivalries and the king was assassinated in 1934. The replacement government was a regency under Crown Prince Paul representing the 11-year-old heir, Petar II.

When World War II broke out, different parts of the country favored different alliances. The Croats in the north wanted to ally with Germany while the Serbs in the south favored the Allies. The underground Communist Party of Yugoslavia not surprisingly looked to the Soviet Union. The country managed to maintain peaceful relations with everyone until heavy German pressure convinced Prince Paul to ally with the Nazis. This provoked widespread resistance among the population, which proceeded to overthrow him. “Seeing that Yugoslavia could not be concretely made a reliable ally to secure the Balkan Peninsula, Adolf Hitler decided to occupy the country. The Yugoslavian military surrendered to the joint-invasion by Germany, Italy, Hungary, and Bulgaria on 17 Apr 1941. The royal family and the government fled to Britain” (Chen, “Yugoslavia”). Two underground resistance groups sprang up. The Chetniks took a more pro-Yugoslavia stance, biding its time while building up strength. The Communists, led by Josip Broz Tito, fought against both the occupying nations and the Chetniks. The Communist guerrillas were very successful in tying down German troops and providing intelligence for the approaching Soviet Army. Soviet troops captured the capital city of Belgrade on 20 October 1944; the partisans captured Sarajevo on 6 April 1945 then took over Zagreb on 9 May.

Map of the Axis occupation of Yugoslavia. Map by Amitchell125, via Wikimedia Commons.

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As the war was drawing to a close, the Allied governments recognized Tito as the de facto prime minister. King Petar was in Britain and called for a referendum to determine the country’s future government. On 29 November 1945 the people voted to remove him but he refused to abdicate. That same day Tito declared the Federal People’s Republic of Yugoslavia, a Communist regime. It remained tied to the Soviet Union until 1948, when Tito detached the country from its ties with that country. In 1963, he renamed his country the Socialist Federal Republic of Yugoslavia. Although not under Soviet control like the rest of eastern Europe, he maintained friendly relations with them. His death in 1980 reignited the ethnic issues that he had kept under control.

Hungary

Hungary came under a joint monarchy with Austria in 1867. Austria-Hungary allied itself with Germany in 1879 and was thus a partner with them in World War I. After its defeat in that war, the partnership was broken up and Hungary again became independent. With no king now that the Austro-Hungarian Empire had been dissolved, there was a struggle for power. A Communist coup in March 1919 created the Hungarian Soviet Republic and oversaw the ensuing “Red Terror.” That came to an end with the rise of Miklos Horthy, former admiral of the Hungarian Navy, who overthrew the Communists and became regent in place of a monarch. Hungary did not regain all the territory it had previously owned. Every political faction in Hungary felt cheated and desired to regain their lands, but the League of Nations would not allow it. That began to change with the rise of Benito Mussolini in Italy and Adolph Hitler in Germany. In the late 1930s, as they began to spread their influence into parts of Europe, the two leaders gave lands with ethnic Hungarians back to their native homeland. This included parts of Czechoslovakia, Romania, and Yugoslavia. This did not sit well with those countries that lost the territories. Isolation from its neighbors made Hungary increasingly dependent on Germany for trade and political support. Hungary allied with Germany in November 1940 and provided troops for the invasion of Yugoslavia in April 1941 and the invasion of the Soviet Union in June.

The Hungarian government began persecuting Jews, in the summer of 1941 deporting 20,000 from the land they had gotten from Czechoslovakia. The following January, Hungarian troops killed 3,000 Jews and Serbs in the annexed Yugoslavian territory. When Hitler demanded that they start deporting Jews from Hungary, however, the government resisted. Although Hungary had signed a treaty of friendship with Yugoslavia in December 1940, Hitler asked for Hungarian troops to assist in the invasion of Yugoslavia. Hungarian Prime Minister Pál Teleki, who had hoped to keep his country a nonbelligerent, found himself torn between two conflicting agreements. Unable to decide which to follow, he committed suicide. Horthy realized he had better cooperate and so they sent troops in with the Nazis in April 1941 and in doing so were rewarded with 8,000 square miles of Yugoslav territory.

Map courtesy of the United States Military Academy Department of History, via emersonkent.com.

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When the Nazis invaded the Soviet Union two months later, Hitler expected Horthy to cooperate. He initially hesitated, but an air raid on the Hungarian city of Kassa (blamed on the Soviets) convinced him otherwise. The 40,000 troops he committed were successful in aiding the offensive, but as the invasion began to slow in the winter Horthy began to have doubts. When Hitler’s Foreign Minister Joachim von Ribbentrop reminded him that the Allies were giving the Soviets free reign to do what the liked in eastern Europe, Horthy’s earlier conflict with Communists convinced him to assist. This time, 200,000 troops were committed. Unfortunately, the German Sixth Army to which they were attached marched into Stalingrad and were unable to march out when the Soviets surrounded and captured the town in February 1943.

Learning that Horthy and the Romanian leader Antonescu had secretly been contacting the Allies, Hitler called Horthy to meet with him in Germany. While there, Nazi troops invaded Hungary and when he returned Horthy found his country occupied. Although he was allowed to keep his position as regent, the parliament came under the control of an opposition party, the Arrow Cross, which did Hitler’s bidding. Horthy at that point was a figurehead.

By September 1944 only Hungary of all the eastern European countries was still allied with Germany. Horthy did his best to contact Moscow. When, on 15 October he announced on the radio that he had signed an armistice with the Soviets, a German commando team kidnapped him and took him to Bavaria. The Soviet advance captured Budapest after a 50-day siege on 13 February 1945. Some 120,000 people died in the siege, split equally between attackers, defenders, and civilians. “Even once the Nazis had been defeated in the city, the horror continued for Hungarian civilians: the Soviet occupation was no better than the Nazi one. Half a million Hungarians were transported to Soviet labour camps and tens of thousands of women and girls were raped. The war had ended for Hungary but another, longer period of suffering was beginning” (Palfri, “How World War II Shaped”).

See also: Czechoslovakia, Nazi Occupation of; Czechoslovakia, Warsaw Pact invasion of; Balkans, Nazi invasion of; Germany, Soviet invasion of; Hungary, Soviet invasion of 1956; Poland, Nazi conquest of; Soviet Union, Nazi invasion of.

References:

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“Czechoslovakia in World War II,” GlobalSecurity.org, n.d., www.globalsecurity.org/military/world/europe/cz-history-ww2.htm, 24 January 2023; Bell, John D., et al., “Bulgaria: World War II,” Encyclopedia Britannica, n.d., www.britannica.com/place/Bulgaria/Bulgarias-transition, 24 January 2023; Bonn, Keith E., Slaughterhouse: The Handbook of the Eastern Front (Bedford, PA: Aberjona Press, 2005); Chen, C. Peter, “Czechoslovakia,” World War II Database, April 2011, ww2db.com/country/czechoslovakia, 24 January 2023; Chen, C. Peter, “Poland,” World War II Database, June 2007, ww2db.com/country/Poland, 23 January 2023; Chen, C. Peter, “Yugoslavia,” February 2014, ww2db.com/country/Yugoslavia, 25 January 2023; Egorov, Boris, “How and Why Romanians Fought Against the Soviets in WWII,” Russia Today, www.rbth.com/history/332573-how-and-why-romanians-fought, 23 January 2023; Palfri, Rita, “How World War II Shaped Modern Hungary,” Euronews, 5 May 2015, www.euronews.com/2015/05/05/how-world-war-ii-shaped-modern-hungary, 25 January 2023; Wotek, Karol, “A Post-War War: The Years of 1944–1963 in Poland,” Warsaw Institute Review, 1 October 2018, warsawinstitute.org/post-war-war-years-1944-1963-poland/, 22 January 2023.

Citation Types

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MLA 9th
, . "Eastern Europe, Soviet Occupation Of." Encyclopedia of Invasions & Conquests, Fourth Edition, edited by Paul K. Davis, Salem Press, 2023. Salem Online, online.salempress.com/articleDetails.do?articleName=GHInv4e_0202.
APA 7th
, . (2023). Eastern Europe, Soviet Occupation Of. In P. K. Davis (Ed.), Encyclopedia of Invasions & Conquests, Fourth Edition. Salem Press. online.salempress.com.
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,. "Eastern Europe, Soviet Occupation Of." Edited by Paul K. Davis. Encyclopedia of Invasions & Conquests, Fourth Edition. Hackensack: Salem Press, 2023. Accessed October 15, 2025. online.salempress.com.