Throughout the 19th century, what we know today as Poland was not a united, independent country; apart from a brief period during the Napoleonic Wars, Polish land was split between the Austro-Hungarian, Prussian (later German) and Russian empires. During the 1800s, the population of Poland grew steadily, from approximately nine million people in 1800 to almost 25 million in 1900; throughout this time, the Polish people and their culture were oppressed by their respective rulers, and cultural suppression intensified following a number of uprisings in the various territories. Following the outbreak of the First World War, it is estimated that almost 3.4 million men from Poland served in the Austro-Hungarian, German and Russian armies, with a further 300,000 drafted for forced labor by the German authorities. Several hundred thousand were forcibly resettled in the region during the course of the war, as Poland was one of the most active areas of the conflict. For these reasons, among others, it is difficult to assess the extent of Poland's military and civilian fatalities during the war, with most reliable estimates somewhere between 640,000 and 1.1 million deaths. In the context of present-day Poland, it is estimated that the population fell by two million people in the 1910s, although some of this was also due to the Spanish Flu pandemic that followed in the wake of the war.

Poland 1918-1945

After more than a century of foreign rule, an independent Polish state was established by the Allied Powers in 1918, although it's borders were considerably different to today's, and were extended by a number of additional conflicts. The most significant of these border conflicts was the Polish-Soviet War in 1919-1920, which saw well over 100,000 deaths, and victory helped Poland to emerge as the Soviet Union's largest political and military rival in Eastern Europe during the inter-war period. Economically, Poland struggled to compete with Europe's other powers during this time, due to its lack of industrialization and infrastructure, and the global Great Depression of the 1930s exacerbated this further. Political corruption and instability was also rife in these two decades, and Poland's leadership failed to prepare the nation for the Second World War. Poland had prioritized its eastern defenses, and some had assumed that Germany's Nazi regime would see Poland as an ally due to their shared rivalry with the Soviet Union, but this was not the case. Germany invaded Poland on September 1, 1939, in the first act of the War, and the Soviet Union launched a counter invasion on September 17; Germany and the Soviet Union had secretly agreed to do this with the Molotov-Ribbentrop Pact in August, and had succeeded in taking the country by September's end. When Germany launched its invasion of the Soviet Union in 1941 it took complete control of Poland, which continued to be the staging ground for much of the fighting between these nations. It has proven difficult to calculate the total number of Polish fatalities during the war, for a variety of reasons, however most historians have come to believe that the figure is around six million fatalities, which equated to almost one fifth of the entire pre-war population; the total population dropped by four million throughout the 1940s. The majority of these deaths took place during the Holocaust, which saw the Nazi regime commit an ethnic genocide of up to three million Polish Jews, and as many as 2.8 million non-Jewish Poles; these figures do not include the large number of victims from other countries who died after being forcefully relocated to concentration camps in Poland.

Post-war Poland

The immediate aftermath of the war was also extremely unorganized and chaotic, as millions were forcefully relocated from or to the region, in an attempt to create an ethnically homogenized state, and thousands were executed during this process. A communist government was quickly established by the Soviet Union, and socialist social and economic policies were gradually implemented over the next decade, as well as the rebuilding, modernization and education of the country. In the next few decades, particularly in the 1980s, the Catholic Church, student groups and trade unions (as part of the Solidarity movement) gradually began to challenge the government, weakening the communist party's control over the nation (although it did impose martial law and imprison political opponent throughout the early-1980s). Increasing civil unrest and the weakening of Soviet influence saw communism in Poland come to an end in the elections of 1989. Throughout the 1990s, Poland's population growth stagnated at around 38.5 million people, before gradually decreasing since the turn of the millennium, to 37.8 million people in 2020. This decline was mostly due to a negative migration rate, as Polish workers could now travel more freely to Western Europea...

It is estimated that the Second World War was responsible for the deaths of approximately 3.76 percent of the world's population between 1939 and 1945. In 2022, where the world's population reached eight billion, this would be equal to the death of around 300 million people.

The region that experienced the largest loss of life relative to its population was the South Seas Mandate - these were former-German territories given to the Empire of Japan through the Treaty of Versailles following WWI, and they make up much of the present-day countries of the Marshall Islands, Micronesia, the Northern Mariana Islands (U.S. territory), and Palau. Due to the location and strategic importance of these islands, they were used by the Japanese as launching pads for their attacks on Pearl Harbor and in the South Pacific, while they were also taken as part of the Allies' island-hopping strategy in their counteroffensive against Japan. This came at a heavy cost for the local populations, a large share of whom were Japanese settlers who had moved there in the 1920s and 1930s. Exact figures for both pre-war populations and wartime losses fluctuate by source, however civilian losses in these islands were extremely high as the Japanese defenses resorted to more extreme measures in the war's final phase.

This graph shows the total population of Estonia, Latvia and Lithuania in the years between 1922 and 1935, as well as the total number of males and females. After the First World War the Baltic states began claiming their independence from tsarist Russia, as the events of the Russian Revolution took place. Inter-war Estonia The Estonian War of Independence from 1918 to 1920 led to the country's first period of independence, until it became occupied by the Soviet Union again in 1940 during the Second World War. After Estonia gained independence the country experienced a period of political turmoil, including a failed coup d'etat in 1924, and was hit hard by the Great Depression in 1929 before things became more stable in the mid 1930s. Between 1939 and 1945 Estonia's population was devastated by the Second World War, with some estimates claiming that as many as 7.3 percent of all civilians perished as a result of the conflict. From the graph we can see the population grew by 119 thousand people during the 12 years shown, growing from 1.107 million to 1.126 million. The number of women was also higher than the number of men during this time, by 67 thousand in 1922 and 68 thousand in 1934. Inter-war Latvia For Latvia, Independence was a hard-won struggle that had devastated the population in the late 1910s. Similarly to Estonia, the advent of independence brought many challenges to Latvia, and a period of political and economic turmoil followed, which was exacerbated by the Great Depression in 1929. After economic recovery began in 1933, and a coup d'etat established stricter control in 1934, the Latvian economy and political landscape became more stable and the quality of life improved. This lasted until the Second World War, where Latvia became one of the staging grounds of Germany's war against Soviet Russia, and approximately 12.5 percent of all civilians died. From the data we can see that Latvia's population between 1925 and 1935 grew steadily by 95,000 in this decade, with the number of men and women growing at a similar rate. Inter-war Lithuania Lithuania's experience in the interwar period was slightly different to that of Latvia and Estonia. The end of the First World War led to a growing movement for independence from German, Russian or Polish influence, however these countries were reluctant to cede control to one another, and independence was finally achieved in 1922. A right wing dictatorship was established in 1926, which maintained political and civil control until the outbreak of the Second World War, however interference from other nations, particularly Germany, was ever-present in Lithuanian economic activity. From the graph we have only one set of figures, showing that the Lithuanian population was just over 2 million in 1929, with approximately 5 percent more women than men. World War II again devastated Lithuania's population, with almost 14.4 percent of the entire population falling during the conflict.

Over the course of the Second World War, approximately 44.5 percent of the Soviet population and 8.7 of Soviet territory was occupied by the Axis forces at some point. Despite being allied in the war's early stages, with both countries invading Poland in 1939 via the Molotov-Ribbentrop Pact, Germany would launch Operation Barbarossa, the invasion of the USSR, in 1941, which would become the largest military invasion in history. Movement of the Eastern Front The surprise invasion began on June 22, and Axis forces caught the Soviets off-guard, quickly pushing their way eastward along a frontline that stretched from the Baltic to Black seas. The length of the front-line allowed Axis forces to execute pincer movements around cities and strongholds, which cut off large numbers of Soviet soldiers from their supply lines, as well as preventing reinforcements; in this process millions of Soviet troops were taken as prisoner. Within three weeks, the Germans had taken much of present-day Poland, Belarus, and the Baltic states, before taking Moldova and Ukraine in September, and pushing into western Russia between September and December. The front lines had reached the outskirts of Moscow by November, before exhaustion and cold weather helped Soviet forces hold the line and stall the German offensive. The Red Army was then able to regroup and turning the Germans' own tactics against them, using two-pronged attacks to encircle large numbers of troops, although harsh weather made this stage of the conflict much slower.

The lines remained fairly static until mid-1942, when the Germans focused their offensive on the south, concentrating on the Caucasian oil fields and the Volga River. By November 1942, Axis forces had pushed into these regions, establishing what would ultimately be the largest amount of occupied Soviet territory during the war. Once again, winter halted the Axis advance, and allowed the Red Army to regroup. Learning from the previous year, the Axis command strengthened their forces near Moscow in anticipation of the Soviet counter-offensive, but were caught off-guard by a second counter-offensive in the south, most famously at Stalingrad. The Battle of Stalingrad would come to epitomize the extreme loss, destruction, and brutality of war on the eastern front, with conflict continuing in the city months after the rest of the Axis forces had been pushed west. As 1943 progressed, the Red Army gained momentum by targeting inferiorly-trained and equipped non-German regiments. The spring then became something of a balancing act for the Axis powers, as the Soviets consistently attacked weak points, and German regiments were transferred to reinforce these areas. In the summer of 1943, the front line was static once more, however the momentum was with the Soviets, who were able to capitalize on victories such as Kursk and gradually force the Axis powers back. By 1944, the Red Army had re-captured much of Ukraine, and had re-taken the south by the summer. When the Western Allies arrived in France in June, the Soviets were already pushing through Ukraine and Belarus, towards Berlin. In August 1944, the last Axis forces were pushed out of Soviet territory, and Soviet forces continued their push towards the German capital, which fell in May 1945. Soviet death toll In addition to the near-five million Soviet troops who died during Operation Barbarossa, millions of civilians died through starvation, areal bombardment, forced labor, and systematic murder campaigns. Due to the nature and severity of Soviet losses, total figures are difficult to estimate; totals of 15-20 million civilians and 7-9 million military deaths are most common. Further estimates suggest that the disruption to fertility, in addition to the high death toll, meant that the USSR's population in 1946 was 40 million lower than it would have been had there been no war.

Life expectancy in Poland was 35.9 in the year 1885, and over the course of the next 135 years, it is expected to have increased to 78.5 by the year 2020. Although life expectancy has generally increased throughout Poland's history, the most noticeable decline came in the 1940s as a result of the Second World War and Holocaust, which caused Poland's population to decline by about 17 percent, which was more than any other country.

Most estimates place the total number of deaths during the Second World War at around 70-85 million people. Approximately 17 million of these deaths (20-25 percent of the total) were due to crimes against humanity carried out by the Nazi regime in Europe. In comparison to the millions of deaths that took place through conflict, famine, or disease, these 17 million stand out due to the reasoning behind them, along with the systematic nature and scale in which they were carried out. Nazi ideology claimed that the Aryan race (a non-existent ethnic group referring to northern Europeans) was superior to all other ethnicities; this became the justification for German expansion and the extermination of others. During the war, millions of people deemed to be of lesser races were captured and used as slave laborers, with a large share dying of exhaustion, starvation, or individual execution. Murder campaigns were also used for systematic extermination; the most famous of these were the extermination camps, such as at Auschwitz, where roughly 80 percent of the 1.1 million victims were murdered in gas chambers upon arrival at the camp. German death squads in Eastern Europe carried out widespread mass shootings, and up to two million people were killed in this way. In Germany itself, many disabled, homosexual, and "undesirables" were also killed or euthanized as part of a wider eugenics program, which aimed to "purify" German society.

The Holocaust Of all races, the Nazi's viewed Jews as being the most inferior. Conspiracy theories involving Jews go back for centuries in Europe, and they have been repeatedly marginalized throughout history. German fascists used the Jews as scapegoats for the economic struggles during the interwar period. Following Hitler's ascendency to the Chancellorship in 1933, the German authorities began constructing concentration camps for political opponents and so-called undesirables, but the share of Jews being transported to these camps gradually increased in the following years, particularly after Kristallnacht (the Night of Broken Glass) in 1938. In 1939, Germany then invaded Poland, home to Europe's largest Jewish population. German authorities segregated the Jewish population into ghettos, and constructed thousands more concentration and detention camps across Eastern Europe, to which millions of Jews were transported from other territories. By the end of the war, over two thirds of Europe's Jewish population had been killed, and this share is higher still when one excludes the neutral or non-annexed territories.

Lebensraum Another key aspect of Nazi ideology was that of the Lebensraum (living space). Both the populations of the Soviet Union and United States were heavily concentrated in one side of the country, with vast territories extending to the east and west, respectively. Germany was much smaller and more densely populated, therefore Hitler aspired to extend Germany's territory to the east and create new "living space" for Germany's population and industry to grow. While Hitler may have envied the U.S. in this regard, the USSR was seen as undeserving; Slavs were the largest major group in the east and the Nazis viewed them as inferior, which was again used to justify the annexation of their land and subjugation of their people. As the Germans took Slavic lands in Poland, the USSR, and Yugoslavia, ethnic cleansings (often with the help of local conspirators) became commonplace in the annexed territories. It is also believed that the majority of Soviet prisoners of war (PoWs) died through starvation and disease, and they were not given the same treatment as PoWs on the western front. The Soviet Union lost as many as 27 million people during the war, and 10 million of these were due to Nazi genocide. It is estimated that Poland lost up to six million people, and almost all of these were through genocide.

Europe's Jewish population in 1939 was around 9.5 million people, and it is estimated that six million of these were ultimately killed by 1945. The persecution of German Jews escalated during the interwar period, particularly after Hitler's ascent to power in 1933, and again after Kristallnacht in 1938. However, the scale of this increased drastically following the German invasions of Poland in 1939 and the USSR in 1941, when Germany annexed regions with some of the largest Jewish populations in Europe. Extermination Camps As part of the "Final Solution to the Jewish Question", the Nazi occupiers established six extermination camps in present-day Poland; these were Auschwitz-Birkenau, Belzec, Chelmno, Majdanek***, Sobibor, and Treblinka. Prisoners, mostly Jews, were transported from all over Europe to these camps. Upon arrival, the majority of victims were sent directly to purpose-built chambers or vans, where they were murdered with carbon monoxide or Zyklon B gas. A relatively small number of prisoners were also forced to dispose of the victims' bodies, which often included their own family members, friends, or persons known to them. Most of the deceased were incinerated, and many of the camp records were destroyed; this means that precise figures for the number of deaths in extermination camps will never be known. It has been estimated that at least 2.7 million Jews were murdered in these six camps; over two thirds of these were killed at Auschwitz or Treblinka. Einsatzgruppen After extermination camps, the most common method of murder was through mass shootings. The majority of these shootings were not carried out by regular soldiers, but specialized task forces known as "Einsatzgruppen". Each group was just a few hundred men each, but they were responsible for some of the largest individual acts of genocide in the war. The largest of these took place at Babi Yar, near Kyiv in 1941, where almost 35,000 victims were beaten, humiliated, and then shot over a two day period. The Einsatzgruppen were most active in the annexed Soviet territories (although additional regiments were active in Poland and the Balkans), and their ranks were often bolstered by local volunteers. It has been estimated that Einsatzgruppen were responsible for the genocide of more than two million people in fewer than six years.