Former eastern territories of Germany

The former eastern territories of Germany () are those provinces or regions east of the current eastern border of Germany (the Oder–Neisse line) which were lost by Germany after World War I and then World War II; having been parts of the German Empire from 1871, and previously, of Prussia and Austria. They include provinces that historically had been considered German, and others that became German following the Unification of Germany in 1871.
The territories lost by Germany to Poland following World War I included areas with predominantly ethnically Polish population, especially the Province of Posen (Greater Poland and Kuyavia), most of the province of West Prussia (see the Polish Corridor), and East Upper Silesia. In addition, the partly Lithuanian-populated Klaipėda Region became part of Lithuania. Further territories lost after World War II included areas which were almost exclusively inhabited by Germans before 1945: East Prussia, Farther Pomerania, Neumark, West Upper Silesia, and almost all of Lower Silesia (except for a small area east of and around Hoyerswerda). The German population of the territories that had not fled in 1945 was expropriated and expelled, forming the majority of the Germans expelled from Eastern Europe. 
The territories lost in both World Wars account for 33% of the pre-1914 German Empire, while land ceded by Germany after World War II constituted roughly 25% of its pre-war Weimar territory. In present-day Germany, the term 'Former eastern territories' usually refers only to those territories lost in World War II. Territories acquired by Poland after World War II were called there the Recovered Territories. These territories had been ruled as part of Poland by the Piast dynasty in the High Middle Ages with the exception of Prussia which was inhabited by Old Prussians and had become predominantly German during the Ostsiedlung. Parts of historic Prussia became part of the Soviet Union as the Kaliningrad Oblast, now forming a Russian exclave.
The post-war border between Germany and Poland along the Oder–Neisse line was defined in August 1945 by the Potsdam Agreement of the leaders of the three Allied Powers, the Soviet Union, the United Kingdom, and the United States; and was formally recognized by East Germany in 1950, by the Treaty of Zgorzelec, under pressure from Stalin. In 1952, recognition of the Oder–Neisse Line as a permanent boundary was one of Stalin's conditions for the Soviet Union to agree to a reunification of Germany (see Stalin Note). The offer was rejected by West German Chancellor Konrad Adenauer. The then official West German government position on the status of former eastern territories of Germany east of the Oder and Neisse rivers was that the areas were "temporarily under Polish [or Soviet] administration", because the border regulation at the Potsdam Conference had been taken as preliminary provisions to be revisited at final Peace Conference, which, also due to the Cold War had been indefinitely postponed. 
In 1970, West Germany recognised the Oder-Neisse line as the western boundary of Poland by the Treaty of Warsaw; and in 1973, the Federal Constitutional Court acknowledged the capability of East Germany to negotiate the Treaty of Zgorzelec as an international agreement binding as a legal definition of its boundaries. In signing the Helsinki Final Act in 1975, both West Germany and East Germany recognised the existing boundaries of post-war Europe, including the Oder-Neisse line, as valid in international law.
In 1990, as part of the reunification of Germany, West Germany accepted clauses in the Treaty on the Final Settlement With Respect to Germany whereby Germany renounced all claims to territory east of the Oder–Neisse line. Germany's recognition of the Oder–Neisse line as the border was formalised by the re-united Germany in the German–Polish Border Treaty on 14 November 1990; and by the repeal of Article 23 of the Basic Law for the Federal Republic of Germany under which German states outside the Federal Republic could formerly have declared their accession.
Germany went from a European territory of 540,857 km² (1914) before the First World War to 357,022 km² after the reunification of Germany (1990).
Usage.
In the Potsdam Agreement the description of the territories transferred is "The former German territories east of the Oder–Neisse line", and permutations on this description are the most commonly used to describe any former territories of Germany east of the Oder–Neisse line.
The name East Germany, a political term, used to be the common colloquial English name for the German Democratic Republic (GDR), and mirrored the common colloquial English term for the other German state of West Germany. When focusing on the period before World War II, "eastern Germany" is used to describe all the territories east of the Elbe (East Elbia), as reflected in the works of sociologist Max Weber and political theorist Carl Schmitt, but because of the border changes in the 20th century, after World War II the term "East Germany" and eastern Germany in English has meant the territory of the German Democratic Republic.
In German there is only one usual term, "Ostdeutschland", meaning East Germany or Eastern Germany. The rather ambiguous German term never gained prevailing use for the GDR as did the English term. Since reunification, "Ostdeutschland" has been commonly used to denote both the historic post-war German Democratic Republic, and its counterpart five successor states in the current reunited Germany. However, because people and institutions in the states traditionally considered as Middle Germany, like the three southern new states Saxony-Anhalt, the Free State of Saxony and the Free State of Thuringia, still use the term Middle Germany when referring to their area and its institutions, the term "Ostdeutschland" is still ambiguous.
Before Second World War.
As various Germanic tribes had moved to Central Europe, West Slavic tribes moved to most of present-day Poland from the 6th century onward. Duke Mieszko I of the Polans, from his stronghold in the Gniezno area, united various neighboring tribes in the second half of the 10th century, forned the first Polish state and became the first historically-recorded Piast duke. His realm bordered the German state, and control over the borderlands would shift back and forth between the two polities over the centuries to come.
Mieszko's son and successor, Duke Bolesław I Chrobry, upon the 1018 Peace of Bautzen expanded the southern part of the realm but lost control over the lands of Western Pomerania on the Baltic coast. After pagan revolts and a Bohemian invasion in the 1030s, Duke Casimir I the Restorer (reigned 1040-1058) again united most of the former Piast realm, including Silesia and Lubusz Land, on both sides of the middle Oder River but without Western Pomerania, which returned to of the Polish state only under Bolesław III Wrymouth from 1116 to 1121, when the noble House of Griffins established the Duchy of Pomerania. On Bolesław's death in 1138, Poland was for almost 200 years was subjected to fragmentation and ruled by Bolesław's sons and by their successors, who were often in conflict with one another. Władysław I the Elbow-high, who was crowned king of Poland in 1320, achieved a partial reunification, but the Silesian and Masovian duchies remained independent Piast holdings.
In the 12th to the 14th centuries, Germab settlers, most of whom spoke Low German, moved into Central and Eastern Europe in a migration process known as the "Ostsiedlung", and the Hanseatic League dominated the shores of the Baltic Sea. In Pomerania, Brandenburg, Prussia and Silesia, the former West Slav (Polabian Slavs and Poles) or Baltic population became minorities in the course of the following centuries, but substantial numbers of them inhabitants remained in areas such as Upper Silesia. In Greater Poland and in Eastern Pomerania (Pomerelia), German settlers formed a minority. Some of the territories, such as Pomerelia and Masovia, reunited with Poland during the 15th and 16th centuries. Others became more firmly incorporated into German polities.
In 1815, the Congress of Vienna established the German Confederation (German: Deutscher Bund) as an association of 39 German-speaking states in Central Europe. That established the boundaries of Germany for much of the 19th century, including Pomerania, East Brandenburg and Silesia but excluding German-speaking lands in the eastern portion of the Kingdom of Prussia (East Prussia, West Prussia and Posen), as well as the German cantons of Switzerland and the French region of Alsace.
Important military events from German history include battles such as Frederick the Great’s victories at Mollwitz in 1741, Hohenfriedberg in 1745, Leuthen (1757) and Zorndorf (1758), and his defeats at Gross-Jägersdorf in 1757 and Kunersdorf in 1759. Historian Norman Davies describes Kunersdorf as "Prussia's greatest disaster" and the inspiration for Christian Tiedge's "Elegy" to "Humanity butchered by Delusion on the Altar of Blood". During the Napoleonic Wars the Pomeranian town of Kolberg was besieged in 1807 (inspiring a Second World War Nazi propaganda film), and the French Grande Armée was victorious at Eylau in East Prussia in the same year. The Treaties of Tilsit were separately signed in the selfsame town in July 1807 between Napoleon and the Russians and the Prussians. The Iron Cross, Germany's highest military honour, was established bur not awarded by King Frederick William III at Breslau on 17 March 1813. In World War I, Paul von Hindenburg won critical victories at Tannenberg and the Masurian Lakes and ejected Russian forces from East Prussia.
Pomerania.
The Pomeranian areas of the former eastern territories of Germany correspond to today's Polish Western Pomerania. The region had been under short Polish rule several times from the late 10th century and in the 12th century, but Poland failed to achieve the permanent integration of the region's Pomeranian tribes. An independent Duchy under the House of Griffin was constituted in the area. Briefly under suszeranity of the Duchy of Saxony and of Denmark, Pomerania permantently stayed with the Holy Roman Empire and succeeding German states from 1227 onward. By the end of the Middle Ages, by influx of German settlers, the founding of towns under the German town law, the influence of German customs and the trade of the Hanse had turned the area into a German-speaking land.
At the turn of the 20th century, the total population of the province of almost 1.7 million inhabitants had no sizable minority of Polish-speakers.
Danzig, Lauenburg and Bütow Land.
The region of Pomerelia or Gdańsk Pomerania became part of the monastic state of the Teutonic Knights in 1308, after conflicts between Władysław I Łokietek and the local rulers had erupted. Under the Teutonic Order, the land advanced economically by influx of western, mainly German-speaking farmers, traders and craftsmen. 
In the Second Peace of Thorn, most of the region became part of Royal Prussia, which formed an autonomous province loyal to the Polish king. The region its autonomy, governing itself and maintaining its own laws, customs, rights and German language. After the first two Partitions of Poland in 1772 and 1793, the region with its large number of German-speakers was annexed by Prussia, forming the province of West Prussia. 
A small area in the west of Pomerelia, the Lauenburg and Bütow Land, was granted to the rulers of Pomerania as a Polish fief before it was reintegrated with Poland in 1637. It was later again transformed into a Polish fief, which it remained until the First Partition of Poland. The Prussian area was formed from Royal Prussia in 1773.
East Brandenburg (Neumark).
The medieval Lubusz Land, on both sides of the Oder River up to the Spree in the west, including Lubusz (Lebus) itself, also formed part of Mieszko's realm. Poland lost Lubusz when the Silesian duke Bolesław II Rogatka sold it to the Ascanian margraves of Brandenburg in 1249. Brandenburg also acquired the castellany of Santok from Duke Przemysł I of Greater Poland and made it the nucleus of its Neumark ("New March") region. The Bishopric of Lebus remained a suffragan of the Archdiocese of Gniezno until 1424, when it passed under the jurisdiction of the Archbishopric of Magdeburg. The Lubusz Land was part of the Lands of the Bohemian (Czech) Crown from 1373 to 1415.
Parts of Greater Poland and Kuyavia.
Some of the former eastern territory east of the Lubusz Land had formed the western parts of the Polish provinces of Pomerelia and Greater Poland ("Polonia Maior"), being lost to Prussia in the First Partition (the Pomerelian parts) and the Second Partition (the remainder). During the Napoleonic eta the Greater Polish territories formed part of the Duchy of Warsaw, but after the Congress of Vienna, Prussia reclaimed them as part of the Grand Duchy of Posen (Poznań), later the Province of Posen.
Silesia.
Around AD 1, various German tribes settled in the area of Silesia. After the German tribes had moved west during the Migration Period, Slavic tribes began to settle the area. In the 10th century Mieszko I of Poland made Silesia part of his empire. From the 10th century to the 12th century, Silesia was contested between Bohemia and Poland. Several independent duchies formed that strived for independence from Poland ans attached themselves to the Holy Roman Empire. In the 14th century, the Treaty of Trentschin had King Casimir III the Great give up all Polish claims to Silesia and ceded the Duchies of Silesia to the Kingdom of Bohemia, an Electorate of the Holy Roman Empire. Briefly under Hungarian rule, Silesia passed to the Holy Roman Empire to the Habsburg Monarchy of Austria in 1526. Frederick the Great conquered Silesia in 1742, and the Habsburg Monarchy ceded most of the region to the Kingdom of Prussia in the Treaties of Breslau and Berlin. 
The first German colonists arrived in the late 12th century, and large-scale German settlement started in the early 13th century during the reign of Henry I, to populate the sparsely-settled land. By the late 14th century, 130 towns and 1300 villages had been founded under German law. Typical Silesian cities such as Hirschberg, Löwenberg, Goldberg, founded to attract German settlers, had a typical architecture of being centered around a central square, the Ring, which became known in Polish as Rynek. Germans also started settling mountaineous areas, where the Piast rulers had only established fortifications.
Most of Lower Silesia became German-speaking, but Polish was used in Upper Silesia and Middle Silesia north of the Ode River. Here the Germans who arrived during the Middle Ages became mostly Polonized. The Polish-speaking parts of Lower and Middle Silesia, commonly described until the late 19th century as the "Polish side", were mostly Germanised in the 18th and 19th centuries except for some areas along the northeastern frontier.
Warmia and Masuria.
The northern territories of Warmia and Masuria form the areas of the former eastern territories of Germany that had been Polish fiefs. Originally inhabited by pagan Old Prussians, the regions became were conquered and incorporated into the state of the Teutonic Knights in the 13th and 14th centuries. By the Second Peace of Thorn (1466), Warmia was awarded to the Polish Crown as part of Royal Prussia but with considerable autonomy, and Masuria became part of a Polish fief, first as part of the Teutonic state, and from 1525 as part of the secular Ducal Prussia. Prussia took direct control of the region in the First Partition of Poland (1772) and in 1773 included the area in the newly formed province of East Prussia.
Foundation of German Empire, 1871.
At the time of the foundation of the German Empire in 1871, the Kingdom of Prussia was the largest and dominant part of the empire. Prussian territory east of the later Oder–Neisse line included West Prussia and Posen (taken by Prussia in the first two Partitions of Poland in the 18th century) and Silesia, East Brandenburg and Pomerania. Later, the territories would come to be called in Germany "Ostgebiete des deutschen Reiches" (Eastern territories of the German Empire). After 1871, the boundaries of Germany came to be understood as having been extended to include the whole of Prussian territory.
Treaty of Versailles, 1919.
The Treaty of Versailles of 1919, which ended the war, restored the independence of Poland, known as the Second Polish Republic, and Germany was compelled to cede territories to it, most of which were taken by Prussia in the three Partitions of Poland and had been part of the Kingdom of Prussia and later the German Empire for over 100 years. The territories ceded to Poland in 1919 were those with an apparent Polish majority, such as the Province of Posen and the so-called Polish Corridor. Diciding the Polish Corridor was also done to grant Poland access to the sea, at the loss of Germany's connection with eEst Prussia, which became an exclave. 
However, in areas such as Upper Silesia, no clear division between the mostly bilingual population was possible. After a first plebiscite, Upper Silesia was to stay part of Germany's territory. However, after the Silesian Uprisings, the area was divided.
The parts of the former Province of Posen and of West Prussia that were not restored as part of the Second Polish Republic were administered as Grenzmark Posen-Westpreußen (the German Province of Posen–West Prussia) until 1939.
German annexation of Hultschin Area and Memel Territory.
In October 1938 Hlučín Area ("Hlučínsko" in Czech, "Hultschiner Ländchen" in German) of Moravian-Silesian Region, which had been ceded to Czechoslovakia under the Treaty of Versailles was annexed by the Third Reich as a part of areas lost by Czechoslovakia in accordance with the Munich agreement. However, as distinct from other lost Czechoslovakian domains, it was not attached to Sudetengau (the administrative region covering the Sudetenland) but to Prussia (Upper Silesia).
By late 1938, Lithuania had lost control over the situation in the Memel Territory, which had been annexed by Lithuania in the Klaipėda putsch. In the early hours of 23 March 1939, after a political ultimatum caused a Lithuanian delegation to travel to Berlin, Lithuanian Foreign Minister Juozas Urbšys and German Foreign Minister Joachim von Ribbentrop signed the "Treaty of the Cession of the Memel Territory to Germany" in exchange for a Lithuanian Free Zone in the port of Memel that used the facilities erected in the previous years.
In the interwar period, the German administration, both Weimar and Nazi, conducted a massive campaign of renaming of thousands of placenames, to remove traces of Polish, Lithuanian and Old Prussian origin.
Second World War.
German occupation of Poland, 1939–1945.
Between the two world wars, many in Germany claimed that the territory ceded to Poland in 1919–1922 should be returned to Germany. That claim was one of the justifications for the German invasion of Poland in 1939, which heralded the start of the Second World War. The Third Reich annexed the former German lands, comprising the "Polish Corridor", West Prussia, the Province of Posen and parts of eastern Upper Silesia. The council of the Free City of Danzig voted to become a part of Germany again, but Poles and Jews were deprived of their voting rights and all non-Nazi political parties were banned. In addition to taking territories lost in 1919, Germany also took additional land that had never been German.
Two decrees by Adolf Hitler (8 and 12 October 1939) divided the annexed areas of Poland into administrative units:
The territories had an area of 94,000 km2 and a population of 10,000,000 people. Throughout the war, the annexed Polish territories were subject to German colonisation. Because of the lack of settlers from Germany itself, the colonists were primarily ethnic Germans relocated from other parts of Eastern Europe. The ethnic Germans were then resettled in homes from which the Poles had been expelled.
The remainder of Polish territory was annexed by the Soviet Union (see Molotov–Ribbentrop Pact) or made into the German-controlled General Government occupation zone.
After the German attack on the Soviet Union in June 1941, the district of Białystok, which included the Białystok, Bielsk Podlaski, Grajewo, Łomża, Sokółka, Volkovysk and Grodno Counties, was "attached to" but not incorporated into East Prussia, and Eastern Galicia (District of Galicia), which included the cities of Lwów, Stanislawów and Tarnopol, was made part of the General Government.
With the imminence of the German defeat, a first agreement on the occupation zones was made in Lonon 1944, which made Central Germany and the German East fall under Soviet occupation. In the Atlantic Charter, the Western Allies had declared that any territorial adjustments must be in accord with the wishes of the peoples concerned.
Yalta Conference.
The final decision to move Poland's boundary westward was made by the United States, the United Kingdom and the Soviet Union at the Yalta Conference in February 1945, shortly before the end of the war. The precise location of the border was left open, and the western Allies also accepted in general the principles of the Oder River being the future western border of Poland and of population transfer being the way to prevent future border disputes. The open questions were whether the border should follow the Eastern or Lusatian Neisse rivers and whether Stettin, the traditional seaport of Berlin, should remain in Germany or be included in Poland.
Originally, Germany was to retain Stettin, and the Poles were to annex East Prussia with Königsberg. Eventually, however, Stalin decided that he wanted Königsberg as a year-round warm water port for the Soviet Navy and argued that the Poles should receive Stettin instead. The wartime Polish government-in-exile had little say in the decisions.
The Yalta Conference agreed to split Germany into four occupation zones after the war, with a quadripartite occupation of Berlin as well, prior to the reunification of Germany. The status of Poland was discussed but was complicated by the fact that Poland was then controlled by the Red Army. The conference agreed to reorganise the Provisionary Polish Government, which had been set up by the Red Army, by the inclusion of other groups such as the Polish Provisional Government of National Unity and to have democratic elections. Thar effectively excluded the Polish government-in-exile, which had been evacuated in 1939. The conference agreed that the Polish eastern border would follow the Curzon Line and that Poland would receive substantial territorial compensation in the west from Germany, but the exact border was to be determined later. A "Committee on Dismemberment of Germany" was to be set up to decide whether Germany was to be divided into six nations and, if so, what borders and interrelations the new German states would have.
Post World War II.
After the War, the so-called "German question" was an important factor of post-war German and European history and politics. The debate affected Cold War politics and diplomacy and played an important role in the negotiations leading up to the reunification of Germany in 1990. In 1990 Germany officially recognized its present eastern border at the time of its reunification in the Treaty on the Final Settlement with Respect to Germany, ending any residual claims to sovereignty that Germany may have had over any territory east of the Oder–Neisse line.
Between 1945 and the 1970s the government of West Germany referred to these territories as "former German territories temporarily under Polish and Soviet administration". This terminology was used in relation to territories of eastern Germany within the 1937 Germany border, and was based on the terminology used in the Potsdam Agreement. It was used only by the Federal Republic of Germany; but the Polish and Soviet governments objected to the obvious implication that these territories should someday revert to Germany. The Polish government preferred to use the phrase Recovered Territories, asserting a sort of continuity because parts of these territories had centuries previously been ruled by ethnic Poles.
In the early history of West Germany, refugee organizations were an important political factor, demanding for Germany to never renounce the land that was deemed still part of Germany. However, contrary to the official claims, the bulk of the expelleés likely would not have a real intent of returning to their homeland.
Potsdam Agreement, 1945.
After World War II, several memoranda of the US State Department warned against awaring Poland such extensive lands, apprehensive of creation of new long-standing tension in the area. Particulary, the State Department acknowledged that Polish claims to Lower Silesia had no ethnic or historic justification.