paragraph_text: Czechoslovakia, of all the East European countries, entered the postwar era with a relatively balanced social structure and an equitable distribution of resources. Despite some poverty, overall it was a country of relatively well-off workers, small-scale producers, farmers, and a substantial middle class. Nearly half the population was in the middle-income bracket. Ironically, perhaps, it was balanced and relatively prosperous Czechoslovakia that carried nationalization and income redistribution further than any other East European country. By the mid-1960s, the complaint was that leveling had gone too far. Earning differentials between blue-collar and white-collar workers were lower than in any other country in Eastern Europe. Further, equitable income distribution was combined in the late 1970s with relative prosperity. Along with East Germany and Hungary, Czechoslovakia enjoyed one of the highest standards of living of any of the Warsaw Pact countries through the 1980s.

paragraph_text: Poland's nobility were also more numerous than those of all other European countries, constituting some 10–12% of the total population of historic Polish–Lithuanian Commonwealth also some 10–12% among ethnic Poles on ethnic Polish lands (part of Commonwealth), but up to 25% of all Poles worldwide (szlachta could dispose more of resources to travels and/or conquering), while in some poorer regions (e.g., Mazowsze, the area centred on Warsaw) nearly 30%. However, according to  szlachta comprised around 8% of the total population in 1791 (up from 6.6% in the 16th century), and no more than 16% of the Roman Catholic (mostly ethnically Polish) population. It should be noted, though, that Polish szlachta usually incorporated most local nobility from the areas that were absorbed by Poland–Lithuania (Ruthenian boyars, Livonian nobles, etc.) By contrast, the nobilities of other European countries, except for Spain, amounted to a mere 1–3%, however the era of sovereign rules of Polish nobility ended earlier than in other countries (excluding France) yet in 1795 (see: Partitions of Poland), since then their legitimation and future fate depended on legislature and procedures of Russian Empire, Kingdom of Prussia or Habsburg Monarchy. Gradually their privileges were under further limitations to be completely dissolved by March Constitution of Poland in 1921.

paragraph_text: NATO has added new members seven times since its founding in 1949, and since 2017 NATO has had 29 members. Twelve countries were part of the founding of NATO: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States. In 1952, Greece and Turkey became members of the Alliance, joined later by West Germany (in 1955) and Spain (in 1982). In 1990, with the reunification of Germany, NATO grew to include the former country of East Germany. Between 1994 and 1997, wider forums for regional cooperation between NATO and its neighbors were set up, including the Partnership for Peace, the Mediterranean Dialogue initiative and the Euro - Atlantic Partnership Council. In 1997, three former Warsaw Pact countries, Hungary, the Czech Republic, and Poland, were invited to join NATO. After this fourth enlargement in 1999, the Vilnius group of The Baltics and seven East European countries formed in May 2000 to cooperate and lobby for further NATO membership. Seven of these countries joined in the fifth enlargement in 2004. The Adriatic States Albania and Croatia joined in the sixth enlargement in 2009, Montenegro in 2017.

paragraph_text: The Soviet Union created the Eastern Bloc of countries that it occupied, annexing some as Soviet Socialist Republics and maintaining others as satellite states that would later form the Warsaw Pact. The United States and various western European countries began a policy of "containment" of communism and forged myriad alliances to this end, including NATO. Several of these western countries also coordinated efforts regarding the rebuilding of western Europe, including western Germany, which the Soviets opposed. In other regions of the world, such as Latin America and Southeast Asia, the Soviet Union fostered communist revolutionary movements, which the United States and many of its allies opposed and, in some cases, attempted to "roll back". Many countries were prompted to align themselves with the nations that would later form either NATO or the Warsaw Pact, though other movements would also emerge.

paragraph_text: The 2005 NATO Headquarters summit was a NATO summit held in the NATO Headquarters, Brussels, Belgium on February 22, 2005. During this summit, NATO leaders reaffirmed their support for building stability in the Balkans, Afghanistan and Iraq, and commit to strengthening the partnership between NATO and the European Union.

paragraph_text: The Nazi regime under Adolf Hitler came to power in 1933, and along with Mussolini's Italy sought to gain control of the continent by the Second World War. Following the Allied victory in the Second World War, Europe was divided by the Iron Curtain. The countries in Southeastern Europe were dominated by the Soviet Union and became communist states. The major non-communist Southern European countries joined a US-led military alliance (NATO) and formed the European Economic Community amongst themselves. The countries in the Soviet sphere of influence joined the military alliance known as the Warsaw Pact and the economic bloc called Comecon. Yugoslavia was neutal.

paragraph_text: In 1956, following the declaration of the Imre Nagy government of withdrawal of Hungary from the Warsaw Pact, Soviet troops entered the country and removed the government. Soviet forces crushed the nationwide revolt, leading to the death of an estimated 2,500 Hungarian citizens.

paragraph_text: The Warsaw Treaty's organization was two-fold: the Political Consultative Committee handled political matters, and the Combined Command of Pact Armed Forces controlled the assigned multi-national forces, with headquarters in Warsaw, Poland. Furthermore, the Supreme Commander of the Unified Armed Forces of the Warsaw Treaty Organization which commands and controls all the military forces of the member countries was also a First Deputy Minister of Defense of the USSR, and the Chief of Combined Staff of the Unified Armed Forces of the Warsaw Treaty Organization was also a First Deputy Chief of the General Staff of the Armed Forces of the USSR. Therefore, although ostensibly an international collective security alliance, the USSR dominated the Warsaw Treaty armed forces.

paragraph_text: The Polish nobility enjoyed many rights that were not available to the noble classes of other countries and, typically, each new monarch conceded them further privileges. Those privileges became the basis of the Golden Liberty in the Polish–Lithuanian Commonwealth. Despite having a king, Poland was called the nobility's Commonwealth because the king was elected by all interested members of hereditary nobility and Poland was considered to be the property of this class, not of the king or the ruling dynasty. This state of affairs grew up in part because of the extinction of the male-line descendants of the old royal dynasty (first the Piasts, then the Jagiellons), and the selection by the nobility of the Polish king from among the dynasty's female-line descendants.

paragraph_text: Of the 29 member countries, two are located in North America (Canada and the United States) and 27 are European countries while Turkey is in Eurasia. All members have militaries, except for Iceland which does not have a typical army (but does, however, have a coast guard and a small unit of civilian specialists for NATO operations). Three of NATO's members are nuclear weapons states: France, the United Kingdom, and the United States. NATO has 12 original founding member nation states, and from 18 February 1952 to 6 May 1955, it added three more member nations, and a fourth on 30 May 1982. After the end of the Cold War, NATO added 13 more member nations (10 former Warsaw Pact members and three former Yugoslav republics) from 12 March 1999 to 5 June 2017.

paragraph_text: The 14.5×114mm (.57 Cal) is a heavy machine gun and anti-materiel rifle cartridge used by the Soviet Union, the former Warsaw Pact, modern Russia, and other countries.

paragraph_text: Prior to the Reformation, the Polish nobility were mostly either Roman Catholic or Orthodox with a small group of Muslims. Many families, however, soon adopted the Reformed faiths. After the Counter-Reformation, when the Roman Catholic Church regained power in Poland, the nobility became almost exclusively Catholic, despite the fact that Roman Catholicism was not the majority religion in Commonwealth (the Catholic and Orthodox churches each accounted for some 40% of all citizens population, with the remaining 20% being Jews or members of Protestant denominations). In the 18th century, many followers of Jacob Frank joined the ranks of Jewish-descended Polish gentry. Although Jewish religion wasn't usually a pretext to block or deprive of noble status, some laws favoured religious conversion from Judaism to Christianity (see: Neophyte) by rewarding it with ennoblement.

paragraph_text: Germany has a network of 227 diplomatic missions abroad and maintains relations with more than 190 countries. As of 2011, Germany is the largest contributor to the budget of the European Union (providing 20%) and the third largest contributor to the UN (providing 8%). Germany is a member of NATO, the OECD, the G8, the G20, the World Bank and the IMF. It has played an influential role in the European Union since its inception and has maintained a strong alliance with France and all neighbouring countries since 1990. Germany promotes the creation of a more unified European political, economic and security apparatus.The development policy of Germany is an independent area of foreign policy. It is formulated by the Federal Ministry for Economic Cooperation and Development and carried out by the implementing organisations. The German government sees development policy as a joint responsibility of the international community. It was the world's third biggest aid donor in 2009 after the United States and France.In 1999, Chancellor Gerhard Schröder's government defined a new basis for German foreign policy by taking part in the NATO decisions surrounding the Kosovo War and by sending German troops into combat for the first time since 1945. The governments of Germany and the United States are close political allies. Cultural ties and economic interests have crafted a bond between the two countries resulting in Atlanticism.

paragraph_text: In 1866, the feud between Austria and Prussia finally came to a head. There were several reasons behind this war. As German nationalism grew strongly inside the German Confederation and neither could decide on how Germany was going to be unified into a nation-state. The Austrians favoured the Greater Germany unification but were not willing to give up any of the non-German-speaking land inside of the Austrian Empire and take second place to Prussia. The Prussians however wanted to unify Germany as Little Germany primarily by the Kingdom of Prussia, whilst excluding Austria. In the final battle of the German war (Battle of Königgrätz) the Prussians successfully defeated the Austrians and succeeded in creating the North German Confederation.

paragraph_text: In July 1963 the Mongolian People's Republic asked to join the Warsaw Pact under Article 9 of the treaty. For this purpose a special protocol should have been taken since the text of the treaty applied only to Europe. Due to the emerging Sino-Soviet split, Mongolia remained on observer status. Soviet stationing troops were agreed to stay in Mongolia from 1966.

paragraph_text: For 36 years, NATO and the Warsaw Pact never directly waged war against each other in Europe; the United States and the Soviet Union and their respective allies implemented strategic policies aimed at the containment of each other in Europe, while working and fighting for influence within the wider Cold War on the international stage.

paragraph_text: Before creation of Warsaw Pact, fearing Germany rearmed, Czechoslovak leadership sought to create security pact with East Germany and Poland. These states protested strongly against re-militarization of West Germany. The Warsaw Pact was primarily put in place as a consequence of the rearming of West Germany inside NATO. Soviet leaders, as many European countries in both western and eastern side, feared Germany being once again a military power as a direct threat and German militarism remained a fresh memory among Soviets and Eastern Europeans. As Soviet Union had already bilateral treaties with all of its eastern satellites, the Pact has been long considered 'superfluous', and because of the rushed way in which it was conceived, NATO officials labeled it as a 'cardboard castle'. Previously, in March 1954, the USSR, fearing the restoration of German Militarism in West Germany, requested admission to NATO.

paragraph_text: The North Atlantic Treaty Organization (NATO / ˈneɪtoʊ /; French: Organisation du Traité de l'Atlantique Nord; OTAN), also called the North Atlantic Alliance, is an intergovernmental military alliance between 29 North American and European countries. The organization implements the North Atlantic Treaty that was signed on 4 April 1949. NATO constitutes a system of collective defence whereby its independent member states agree to mutual defence in response to an attack by any external party. NATO's Headquarters are located in Haren, Brussels, Belgium, while the headquarters of Allied Command Operations is near Mons, Belgium.

paragraph_text: The Warsaw Pact (formally, the Treaty of Friendship, Co-operation, and Mutual Assistance, sometimes, informally WarPac, akin in format to NATO) was a collective defense treaty among Soviet Union and seven Soviet satellite states in Central and Eastern Europe in existence during the Cold War. The Warsaw Pact was the military complement to the Council for Mutual Economic Assistance (CoMEcon), the regional economic organization for the communist states of Central and Eastern Europe. The Warsaw Pact was created in reaction to the integration of West Germany into NATO in 1955 per the Paris Pacts of 1954, but it is also considered to have been motivated by Soviet desires to maintain control over military forces in Central and Eastern Europe.

paragraph_text: Horst Teltschik, Kohl's foreign policy advisor, later recalled that Germany would have paid ``100 billion deutschmarks ''if the Soviets demanded it. The USSR did not make such great demands, however, with Gorbachev stating in February 1990 that`` The Germans must decide for themselves what path they choose to follow''. In May 1990 he repeated his remark in the context of NATO membership while meeting Bush, amazing both the Americans and Germans. This removed the last significant roadblock to Germany being free to choose its international alignments, though Kohl made no secret that he intended for the reunified Germany to inherit West Germany's seats in NATO and the EC.

Question: When did the country the top-ranking Warsaw Pact operatives came from, despite it being headquartered in the country known as the nobilities commonwealth, agree to a unified Germany inside NATO?
Answer: May 1990