Polish contribution to World War II
The European Theatre of World War II opened with the German invasion of Poland on Friday September 1, 1939, followed by the Soviet invasion of Poland on September 17, 1939. On 6 October, following the Polish defeat at the Battle of Kock, German and Soviet forces gained full control over Poland. The success of the invasion marked the end of the Second Polish Republic, though Poland never formally surrendered. A Polish Underground State with a government-in-exile that would eventually set up headquarters in London resumed the struggle against the occupying powers. The  Polish forces in the West, as well as in the East and an intelligence service were established outside of Poland, and contributed to the Allied effort throughout the war. Poles made substantial contributions to the Allied effort throughout the war, fighting on land, sea, and in the air. Particularly well-documented was the service of 145 Polish pilots flying British planes under British Command during the Battle of Britain, 79 in mixed squadrons under the RAF after July 1940, 32 in wholly Polish Squadron 303 after 31 August 1940 and 34 in entirely Polish Squadron 302. Other instances of service  flying French planes in the Polish Air Force took place during the Battle of Britain at the same time, and from 1944 the Polish Air Force (also with British planes) was established in Britain. Polish ground troops were present in the North Africa Campaign (siege of Tobruk); the Italian campaign (including the capture of the monastery hill at the Battle of Monte Cassino); and in battles following the invasion of France (the battle of the Falaise pocket; an airborne-brigade parachute drop during Operation Market Garden; and an armored division in the Western Allied invasion of Germany). Polish forces in  the east, fighting alongside the Red army and under Soviet command, took part in the Soviet offensives across Belarus and Ukraine into Poland and across the Vistula and Oder Rivers to Berlin. Some Polish contributions were less visible, notably the prewar and wartime decrypting of German Enigma-machine ciphers by cryptologists Marian Rejewski, Henryk Zygalski, and Jerzy Różycki. An extensive Polish intelligence network also proved of great value to Allied intelligence. In total, the Polish armed forces were the 4th largest Allied forces in Europe, after those of the Soviet Union, United States, and Britain. Invasion of Poland. The invasion  of Polish Second Republic by the military forces of Nazi Germany marked the beginning of World War II in Europe. The Soviets invaded Poland on September 17 German-allied Slovakia invaded also In keeping with the terms of the of the Molotov–Ribbentrop Pact Germany informed the Soviet Union that its forces were nearing the Soviet interest zone in Poland and so urged the Soviet Union to move into its zone. The Soviets had been taken by surprise by the speed of the German advance as they had expected to have several weeks to prepare for an invasion rather than  merely a few days. They did promise to move as quickly as possible. On September 17 the Soviets invaded eastern Poland, forcing the Polish government and military to abandon their plans for a long-term defense in the Romanian bridgehead area. The last remaining Polish Army units capitulated in early October. In accordance with their treaty obligations, the United Kingdom and France declared war on Germany on September 3. Hitler had gambled, incorrectly, that France and Britain would allow him to annex parts of Poland without military reaction. The campaign began on September 1, 1939, one week after the signing  of the Molotov–Ribbentrop Pact containing a secret protocol for the division of Northern and Central Europe into German and Soviet spheres of influence. It ended on October 6, 1939, with Germany and the Soviet Union occupying the entirety of Poland. German losses included approximately 16,000 killed in action, 28,000 wounded, 3,500 missing, over 200 aircraft, and 30% of their armored vehicles. The Polish casualties were around 66,000 dead and 694,000 captured. German losses during the Polish campaign amounted to 50% of all casualties they would suffer until their invasion of USSR in 1941; and the campaign that lasted about  a month consumed eight months worth of supplies. Aid to Jews. There was a substantial group of Poles who risked their lives during the German occupation to save Jews. German-occupied Poland was the only European territory where the Germans punished any kind of help to Jews with death for the helper and his entire family. Even so, Poland was also the only German-occupied country to establish an organization specifically to aid Jews. Known by the cryptonym "Żegota", it provided food, shelter, medical care, money, and false documents to Jews. Most of Żegota's funds came directly from the  Polish Government-in-Exile in Great Britain. Most Jews who survived the German occupation of Poland were saved by Poles unconnected with Żegota. Estimates of Jewish survivors in Poland range from 40,000 to 50,000 to 100,000–120,000. Scholars estimate that it took the work of ten people to save the life of one Polish Jew. Of the individuals awarded medals of "Righteous among the Nations" (given by the State of Israel to non-Jews who saved Jews from extermination during the Holocaust) those who were Polish citizens number the greatest. There are 6,339 Polish men and women recognized as "Righteous" to  this day, amounting to over 25 percent of the total number of 22,765 honorary titles awarded already. Polish resistance. The main resistance force in German-occupied Poland was the Armia Krajowa ("Home Army"; abbreviated "AK"). While AK command said it numbered 400,000 sworn members, only a very small fraction of these was involved in partisan warfare: in 1943 one percent and in 1944 possibly five to ten percent. Throughout most of the war, AK was one of the three largest resistance movements in the war. The AK coordinated its operations with the exiled Polish Government in London and its activity  concentrated on sabotage, diversion and intelligence gathering. Its combat activity was low until 1943 as the army was avoiding suicidal warfare and preserved its very limited resources for later conflicts that sharply increased when the Nazi war machine started to crumble in the wake of the successes of the Red Army in the Eastern Front. Then the AK started a nationwide uprising (Operation Tempest) against Nazi forces. Before that, AK units carried out thousands of raids, intelligence operations, bombed hundreds of railway shipments, participated in many clashes and battles with the German police and Wehrmacht units and conducted tens of  thousands of acts of sabotage against German industry The AK also conducted "punitive" operations to assassinate Gestapo officials responsible for Nazi terror. Following the 1941 German attack on the USSR, the AK assisted the Soviet Union's war effort by sabotaging the German advance into Soviet territory and provided intelligence on the deployment and movement of German forces. After 1943, its direct combat activity increased sharply. German losses to the Polish partisans averaged 850–1,700 per month in early 1944 compared to about 250–320 per month in 1942. In addition to the Home Army, there was an underground ultra-nationalist resistance  force called "Narodowe Siły Zbrojne" (NSZ or "National Armed Forces"), with a fiercely anti-communist stance. It participated in fighting German units, winning many skirmishes. From 1943 onwards, some units took part in battling the "Gwardia Ludowa" and the Polish People's Army PAL, both communist resistance movement. From 1944, the advancing Red Army was also seen as a foreign occupation force, prompting skirmishes with the Soviets as well as Soviet-backed partisans. In the later part of the war, when Soviet partisans started attacking Polish partisans, sympathizers and civilians, all non-communist Polish formations were (to an increasing extent ) becoming involved in actions against the Soviets. The "Armia Ludowa", a Soviet proxy fighting force was another resistance group that was unrelated to the Polish Government in Exile, allied instead to the Soviet Union. As of July, 1944 it incorporated a similar organization, the "Gwardia Ludowa" and the Polish People's Army PAL, and numbered about 6,000 soldiers (although estimates vary). There were separate resistance groups organized by Polish Jews: the right-wing "Żydowski Związek Walki" ("Jewish Fighting Union") (ŻZW) and the more Soviet-leaning "Żydowska Organizacja Bojowa" ("Jewish Combat Organization") (ŻOB). These organisations cooperated little with each other and  their relationship with the Polish resistance varied between occasional cooperation (mainly between ZZW and AK) to armed confrontations (mostly between ŻOB and NZS). Other notable Polish resistance organizations included the "Bataliony Chłopskie" (BCh), a mostly peasant-based organization allied to the AK. At its height the BCh included 115,543 members (1944; with additional LSB and PKB-AK Guard, for the estimated total of 150,250 men, not confirmed). Throughout the war the German state was forced to divert a substantial part of its military forces to keep control over Poland: Intelligence. Polish intelligence supplied valuable intelligence to the Allies; 48% of  all reports received by the British secret services from continental Europe in between 1939 and 1945 came from Polish sources. The total number of those reports is estimated at about 80,000, and 85% of them were deemed high or better quality. Despite Poland becoming occupied, the Polish intelligence network not only survived but grew rapidly, and near the end of the war had over 1,600 registered agents (Another estimate gave around 3500). Western Allies had limited intelligence assets in Central and Eastern Europe, and extensive Polish intelligence network in place proved to be a major asset, even described as "the  only allied intelligence assets on the Continent" following the French capitulation. According to , for the Western Allies, the intelligence provided by the Home Army was considered to be the best source of information on the Eastern Front. During a period of over six and a half years, from late December 1932 to the outbreak of World War II, three mathematician-cryptologists (Marian Rejewski, Henryk Zygalski and Jerzy Różycki) at the Polish General Staff's Cipher Bureau in Warsaw had developed a number of techniques and devices including the "grill" method, Różycki's "clock", Rejewski's "cyclometer" and "card catalog", Zygalski 's "perforated sheets", and Rejewski's "cryptologic bomb" (in Polish, ""bomba", precursor to the later British "Bombe", named after its Polish predecessor) to facilitate decryption of messages produced on the German "Enigma" cipher machine. Just five weeks before the outbreak of World War II, on July 25, 1939, near Pyry in the Kabaty Woods south of Warsaw, Poland disclosed her achievements to France and the United Kingdom, which had, up to that time, failed in all their own efforts to crack the German military Enigma cipher. Had Poland not shared her Enigma-decryption results at Pyry, the United Kingdom might  have been unable to read Enigma ciphers. In the event, intelligence gained from this source, codenamed Ultra, was extremely valuable to the Allied prosecution of the war. While ULTRA's precise influence on its course remains a subject of debate, ULTRA undoubtedly altered the course of the war. As early as 1940, Polish agents (including Witold Pilecki) penetrated German concentration camps, including Auschwitz, and informed the world about Nazi atrocities. Jan Karski is another important Polish resistance fighter who reported to the Polish government in exile and the Western Allies on the situation in German-occupied Poland, especially the destruction  of the Warsaw Ghetto, and the secretive German-Nazi extermination camps. Polish Home Army ("Armia Krajowa", "AK") intelligence was vital to locating and destroying (18 August 1943) the German rocket facility at Peenemünde and to gathering information about Germany's V-1 flying bomb and V-2 rocket. The Home Army delivered to the United Kingdom key V-2 parts after a rocket, fired on 30 May 1944, crashed near a German test facility at Sarnaki on the Bug River and was recovered by the Home Army. On the night of 25–26 July 1944 the crucial parts were flown from occupied Poland to  the United Kingdom in an RAF plane, along with detailed drawings of parts too large to fit in the plane (see "Home Army and V1 and V2"). Analysis of the German rocket became vital to improving Allied anti-V-2 defenses (see Operation Most III). Operations of the II Bureau, the intelligence service of the Polish government in exile, extended beyond Poland and even beyond Europe. Polish agents provided reports on German war production, morale and troop movements, including information on German submarine operations. The II Bureau is reported to have had two agents in the upper levels of the German  high command. Polish intelligence monitored the French fleet at Toulon. Mieczysław Zygfryd Słowikowski has been described as "the only allied agent with a network in North Africa". In July 1941 Mieczysław Słowikowski (codenamed ""Rygor"—Polish for "Rigor") set up "Agency Africa", one of World War II's most successful intelligence organizations. His Polish allies in these endeavors included Lt. Col. Gwido Langer and Major Maksymilian Ciężki (prewar heads, respectively, of Poland's "Biuro Szyfrów", Cipher Bureau, and of its German section, "B.S.-4", which broke Germany's Enigma ciphers). The information gathered by the Agency was used by the Americans and British  in planning the amphibious November 1942 Operation Torch landings in North Africa. These were the first large-scale Allied landings of the war, and their success in turn paved the way for the Allies' Italian campaign. Some Poles also served in other Allied intelligence services, including the celebrated Krystyna Skarbek ("Christine Granville") in the United Kingdom's Special Operations Executive. The researchers who produced the first Polish-British in-depth monograph on Home Army intelligence "(Intelligence Co-operation Between Poland and Great Britain During World War II: Report of the Anglo-Polish Historical Committee" of 2005) and who described contributions  of Polish intelligence to Allied victory as "disproportionally large" have also argued that "the work performed by Home Army intelligence undoubtedly supported the Allied armed effort much more effectively than subversive and guerilla activities." Polish Forces (West). Army. After the country's defeat in the 1939 campaign, the Polish government in exile quickly organized in France a new army of about 75,000 men. In 1940 a Polish Highland Brigade took part in the Battle of Narvik (Norway), and two Polish divisions (First Grenadier Division, and Second Infantry Fusiliers Division) took part in the defense of France, while a Polish motorized  brigade and two infantry divisions were in process of forming. A Polish Independent Carpathian Brigade was formed in French Mandate Syria, to which many Polish troops had escaped from Romania. The Polish Air Force in France had 86 aircraft with one and a half of the squadrons fully operational, and the remaining two and a half in various stages of training. By the fall of France, numerous Polish personnel had died in the fighting (some ) or had been interned in Switzerland (some ). Nevertheless, about 19,000 Polish—about 25% of which were aircrew—were evacuated from France, most alongside other troops  transported from western France to the United Kingdom. In 1941, following an agreement between the Polish government in exile and Joseph Stalin, the Soviets released Polish citizens, from whom a 75,000-strong army was formed in the USSR under General Władysław Anders. Without any support from the Soviets to train, equip and maintain this army, the Polish government in exile followed Anders' advice for a transfer of some (and around civilians), in March and August 1942, across the Caspian Sea to Iran permitting Soviet divisions in occupation there to be released for action. In the Middle East, this "Anders' Army  joined the British Eighth Army, where it formed Polish II Corps. The Polish Armed Forces in the West fought under British command and numbered 195,000 in March 1944 and 165,000 at the end of that year, including about 20,000 personnel in the Polish Air Force and 3,000 in the Polish Navy. At the end of World War II, the Polish Armed Forces in the west numbered 195,000 and by July 1945 had increased to 228,000, most of the newcomers being released prisoners of war and ex-labor camp inmates. Air force. The Polish Air Force first fought in the 1939 	Polish contribution to World War II
25473482	Invasion of Poland. Significantly outnumbered and with its fighters outmatched by more advanced German fighters, remained active up to the second week of the campaign, inflicting significant damage on the Luftwaffe". The "Luftwaffe" lost, to all operational causes, 285 aircraft, with 279 more damaged, while the Poles lost 333 aircraft. After the fall of Poland many Polish pilots escaped via Hungary to France. The Polish Air Force fought in the Battle of France as one fighter squadron GC 1/145, several small units detached to French squadrons, and numerous flights of industry defence (in total, 133 pilots, who achieved 53–57 victories  for a loss of 8 men in combat, what was 7.93% of allied victories). Later, Polish pilots fought in the Battle of Britain, where the Polish 303 Fighter Squadron claimed the highest number of kills of any Allied squadron. From the very beginning of the war, the Royal Air Force (RAF) had welcomed foreign pilots to supplement the dwindling pool of British pilots. On 11 June 1940, the Polish Government in Exile signed an agreement with the British Government to form a Polish Army and Polish Air Force in the United Kingdom. The first two (of an eventual ten) Polish  fighter squadrons went into action in August 1940. Four Polish squadrons eventually took part in the Battle of Britain (300 and 301 Bomber Squadrons; 302 and 303 Fighter Squadrons), with 89 Polish pilots. Together with more than 50 Poles fighting in British squadrons, a total of 145 Polish pilots defended British skies. Polish pilots were among the most experienced in the battle, most of them having already fought in the 1939 September Campaign in Poland and the 1940 Battle of France. Additionally, prewar Poland had set a very high standard of pilot training. The 303 Squadron, named after the Polish –American hero, General Tadeusz Kościuszko, claimed the highest number of kills (126) of all fighter squadrons engaged in the Battle of Britain, even though it only joined the combat on August 30, 1940 These Polish pilots, constituting 5% of the pilots active during the Battle of Britain, were responsible for 12% of total victories in the Battle. The Polish Air Force also fought in 1943 in Tunisia—the Polish Fighting Team (nicknamed "Skalski's Circus")—and in raids on Germany (1940–45). In the second half of 1941 and early 1942, Polish bomber squadrons formed a sixth of the forces available to  RAF Bomber Command but later they suffered heavy losses, with little replenishment possibilities. Polish aircrew losses serving with Bomber Command from 1940 to 1945 were 929 killed. Ultimately eight Polish fighter squadrons were formed within the RAF and had claimed 629 Axis aircraft destroyed by May 1945. By the end of the war, around 19,400 Poles were serving in the RAF. Polish squadrons in the United Kingdom: Navy. Just on the eve of war, three destroyers—representing most of the major Polish Navy ships—had been sent for safety to the United Kingdom (Operation Peking). There they fought alongside the  Royal Navy. At various stages of the war, the Polish Navy comprised two cruisers and a large number of smaller ships. The Polish navy was given a number of British ships and submarines which would otherwise have been unused due to the lack of trained British crews. The Polish Navy fought with great distinction alongside the other Allied navies in many important and successful operations, including those conducted against the . During the war the Polish Navy, which comprised a total of 27 ships (2 cruisers, 9 destroyers, 5 submarines and 11 torpedo boats), sailed a total of 1.2 million nautical  miles, escorted 787 convoys, conducted 1,162 patrols and combat operations, sank 12 enemy ships (including 5 submarines) and 41 merchant vessels, damaged 24 more (including 8 submarines) and shot down 20 aircraft. 450 seamen out of the over 4,000 who served with the Navy lost their lives in action. This does not include a number of minor ships, transports, merchant-marine auxiliary vessels, and patrol boats. Polish Merchant Navy contributed about 137,000 BRT to Allied shipping; losing 18 ships (with capacity of 76,000 BRT) and over 200 sailors during the war. Polish Forces (East). After the Polish government-in-exile  organized the "Anders Army" in 1941 in the Soviet Union in the aftermath of the Operation Barbarossa and evacuated it to the West, Polish communists sought to create a new army, under communist control, out of the many ethnic Poles that remained in the Soviet Union. These were primarily citizens of the prewar Second Polish Republic that had been deported and often imprisoned by the Soviets following the Soviet annexation of Poland's eastern territories, as per the Molotov-Ribbentrop Pact. The Soviet Union created the Union of Polish Patriots (ZPP) in 1943, a communist Polish organization intended to represent  the interest of Poles on Soviet soil and organize this new army. The relocated Poles, along with numbers of Byelorussians, Ukrainians, and Polish Jews, were organized into a division, the nucleus of a force known as the Polish People's Army ("Ludowe Wojsko Polskie", LWP) but colloquially known as the "Berling Army" after its first commander, Zygmunt Berling. The division made its combat debut in October 1943 at the Battle of Lenino. Afterwards, it was rapidly expanded into the 1st Polish Corps, which in turn grew by 1944 into the 1st Polish Army. In 1945, 2nd Polish Army was added  to the LWP. By the end of the war, the LWP numbered about 200,000 front-line soldiers. The Polish communist guerilla force, the Armia Ludowa, was integrated with the Polish People's Army in January 1944. The Polish First Army was integrated in the 1st Belorussian Front with which it entered Poland from Soviet territory in 1944. During the 1944 Warsaw Uprising it liberated the suburb of Praga, but otherwise sat out most of the battle, aside from a series of unsuccessful crossings of the Vistula in mid-September. It took part in battles for Bydgoszcz (Bromberg), Kolobrzeg (Kolberg), Gdańsk  (Danzig) and Gdynia, losing about 17,500 killed in action over the course of the war. In April–May 1945 the 1st Army fought in the final capture of Berlin. The Polish Second Army fought as part of the Soviet 1st Ukrainian Front and took part in the Prague Offensive. In the final operations of the war the casualties of the two armies of the LWP amounted to approximately 67,000. Poles in the German Armed Forces. Hundreds of thousands of former Polish citizens, particularly residents of parts of Poland annexed to Germany, were conscripted into the German Armed Forces. Also, a  number of former Polish citizens, especially members of the prewar German minority in Poland (see "Volksliste"), volunteered for service in the German Armed Forces. On the Western Front, German military personnel of Polish ethnicity, held in prisoner-of-war camps, became a substantial source of manpower for the Polish Armed Forces in the West. Nearly 90,000 former German military personnel were eventually recruited into the Polish Armed Forces in the West. By Victory Day (9 May) in 1945, a third of Polish service members in the West were former members of the German Armed Forces. Battles. Major battles and campaigns  in which Polish regular forces took part: Technology. Weapons. Polish engineers who escaped German-occupied Poland contributed to weapon developments during the war. A Polish/Czech/British team brought the 20 mm Polsten to fruition as a simpler and cheaper to produce but as effective derivative of the 20 mm Oerlikon gun. The Polish Home Army was probably the only World War II resistance movement to manufacture large quantities of weaponry and munitions. In addition to production of pre-war designs they developed and produced during the war the Błyskawica submachine gun, Bechowiec, KIS and Polski Sten machine pistols as  well as the filipinka and sidolówka hand grenades. During the Warsaw Uprising Polish engineers built several armoured cars, such as the Kubuś, which also took part in the fighting. The KIS was designed and made in the Jan Piwnik's "Ponury" ("Grim") guerrilla unit that was operating in Holy Cross Mountains region. It was probably the only kind of modern firearm that could be manufactured in the forest without the need for sophisticated tools and factory equipment during the Second World War. Notes. a Numerous sources state that Polish Army was the fourth biggest Allied fighting contingent. Steven J. Zaloga  wrote that "by the war's end the Polish Army was the fourth largest contingent of the Allied coalition after the armed forces of the Soviet Union, the United States and Great Britain." Jerzy Jan Lerski writes "All in all, the Polish units, although divided and controlled by different political orientation, constituted the fourth largest Allied force, after the American, British and Soviet Armies." M. K. Dziewanowski has noted that "if Polish forces fighting in the east and west were added to the resistance fighters, Poland had the fourth largest Allied army in the war (after the USSR, the U.S.  and Britain)". b Sources vary with regards to what was the largest resistance movement during World War II. As the war progressed, some resistance movements grew larger—and others diminished. Polish territories were mostly freed from Nazi German control in the years 1944–1945, eliminating the need for their respective (anti-Nazi) partisan forces in Poland (although the cursed soldiers continued to fight against the Soviets). Several sources note that Polish Armia Krajowa was the largest resistance movement in Nazi-occupied Europe. For example, Norman Davies wrote "Armia Krajowa (Home Army), the AK, which could fairly claim to be the largest  of European resistance"; Gregor Dallas wrote "Home Army (Armia Krajowa or AK) in late 1943 numbered around 400000, making it the largest resistance organization in Europe"; Mark Wyman wrote "Armia Krajowa was considered the largest underground resistance unit in wartime Europe". Certainly, Polish resistance was the largest resistance until the German invasion of Yugoslavia and the invasion of the Soviet Union in 1941. After that point, the numbers of Soviet partisans and Yugoslav partisans grew rapidly. The number of Soviet partisans quickly caught up and were very similar to that of the Polish resistance. The number of Tito's Yugoslav  partisans were roughly similar to those of the Polish and Soviet partisans in the first years of the war (1941–1942), but grew rapidly in the latter years, outnumbering the Polish and Soviet partisans by 2:1 or more (estimates give Yugoslavian forces about 800,000 in 1945, to Polish and Soviet forces of 400,000 in 1944).