Member states of NATO
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.
Treaty of Versailles
Of the many provisions in the treaty, one of the most important and controversial required ``Germany (to) accept the responsibility of Germany and her allies for causing all the loss and damage ''during the war (the other members of the Central Powers signed treaties containing similar articles). This article, Article 231, later became known as the War Guilt clause. The treaty forced Germany to disarm, make substantial territorial concessions, and pay reparations to certain countries that had formed the Entente powers. In 1921 the total cost of these reparations was assessed at 132 billion marks (then $31.4 billion or £6.6 billion, roughly equivalent to US $442 billion or UK £284 billion in 2018). At the time economists, notably John Maynard Keynes (a British delegate to the Paris Peace Conference), predicted that the treaty was too harsh -- a`` Carthaginian peace'' -- and said the reparations figure was excessive and counter-productive, views that, since then, have been the subject of ongoing debate by historians and economists from several countries. On the other hand, prominent figures on the Allied side such as French Marshal Ferdinand Foch criticized the treaty for treating Germany too leniently.
League of Nations
The composition of the Council was changed several times. The number of non-permanent members was first increased to six on 22 September 1922 and to nine on 8 September 1926. Werner Dankwort of Germany pushed for his country to join the League; joining in 1926, Germany became the fifth permanent member of the Council. Later, after Germany and Japan both left the League, the number of non-permanent seats was increased from nine to eleven, and the Soviet Union was made a permanent member giving the Council a total of fifteen members. The Council met, on average, five times a year and in extraordinary sessions when required. In total, 107 sessions were held between 1920 and 1939.
Warsaw Pact
The eight member countries of the Warsaw Pact pledged the mutual defense of any member who would be attacked. Relations among the treaty signatories were based upon mutual non-intervention in the internal affairs of the member countries, respect for national sovereignty, and political independence. However, almost all governments of those member states were indirectly controlled by the Soviet Union.
History of Germany
In the early 1930s, the worldwide Great Depression hit Germany hard, as unemployment soared and people lost confidence in the government. In January 1933, Adolf Hitler was appointed Chancellor of Germany. His Nazi Party quickly established a totalitarian regime, and Nazi Germany made increasingly aggressive territorial demands, threatening war if they were not met. Remilitarization of the Rhineland came in 1936, then annexation of Austria in the Anschluss and parts of Czechoslovakia with the Munich Agreement in 1938, and further territory of Czechoslovakia in 1939. On 1 September 1939, Germany initiated World War II in Europe with the invasion of Poland. After forming a pact with the Soviet Union in 1939, Hitler and Stalin divided Eastern Europe. After a "Phoney War" in spring 1940, the Germans swept Denmark and Norway, the Low Countries, and France, giving Germany control of nearly all of Western Europe. Hitler invaded the Soviet Union in June 1941.
Israel
Israel has one of the highest ratios of defense spending to GDP of all developed countries, only topped by Oman and Saudi Arabia. In 1984, for example, the country spent 24% of its GDP on defense. By 2006, that figure had dropped to 7.3%. Israel is one of the world's largest arms exporters, and was ranked fourth in the world for weapons exports in 2007. The majority of Israel's arms exports are unreported for security reasons. Since 1967, the United States has been a particularly notable foreign contributor of military aid to Israel: the US is expected to provide the country with $3.15 billion per year from 2013 to 2018. Israel is consistently rated low in the Global Peace Index, ranking 148th out of 162 nations for peacefulness in 2015.
East Prussia
In 1939 the Regierungsbezirk Zichenau was annexed by Germany and incorporated into East Prussia. Parts of it were transferred to other regions, e.g. Suwałki to Regierungsbezirk Gumbinnen and Soldau to Regierungsbezirk Allenstein. Despite Nazi propaganda presenting all of the regions annexed as possessing significant German populations that wanted reunification with Germany, the Reich's statistics of late 1939 show that only 31,000 out of 994,092 people in this territory were ethnic Germans.[citation needed]
Kellogg–Briand Pact
The Kellogg–Briand Pact (or Pact of Paris, officially General Treaty for Renunciation of War as an Instrument of National Policy) is a 1928 international agreement in which signatory states promised not to use war to resolve "disputes or conflicts of whatever nature or of whatever origin they may be, which may arise among them". Parties failing to abide by this promise "should be denied of the benefits furnished by [the] treaty". It was signed by Germany, France, and the United States on 27 August 1928, and by most other states soon after. Sponsored by France and the U.S., the Pact renounced the use of war and calls for the peaceful settlement of disputes. Similar provisions were incorporated into the Charter of the United Nations and other treaties and it became a stepping-stone to a more activist American policy. It is named after its authors, United States Secretary of State Frank B. Kellogg and French foreign minister Aristide Briand. The pact was concluded outside the League of Nations and remains in effect.
Armenia
Armenia is member of Collective Security Treaty Organisation (CSTO) along with Belarus, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan. It participates in NATO's Partnership for Peace (PiP) program and is in a NATO organisation called Euro-Atlantic Partnership Council (EAPC). Armenia has engaged in a peacekeeping mission in Kosovo as part of non-NATO KFOR troops under Greek command. Armenia also had 46 members of its military peacekeeping forces as a part of the Coalition Forces in Iraq War until October 2008.
Aftermath of World War II
As a consequence of the war, the Allies created the United Nations, an organization for international cooperation and diplomacy, similar to the League of Nations. Members of the United Nations agreed to outlaw wars of aggression in an attempt to avoid a third world war. The devastated great powers of Western Europe formed the European Coal and Steel Community, which later evolved into the European Common Market and ultimately into the current European Union. This effort primarily began as an attempt to avoid another war between Germany and France by economic cooperation and integration, and a common market for important natural resources.
Treaty of Versailles
The Treaty of Versailles (French: Traité de Versailles) was the most important of the peace treaties that brought World War I to an end. The Treaty ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919 in Versailles, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of World War I signed separate treaties. Although the armistice, signed on 11 November 1918, ended the actual fighting, it took six months of Allied negotiations at the Paris Peace Conference to conclude the peace treaty. The treaty was registered by the Secretariat of the League of Nations on 21 October 1919.
Ukraine
After the dissolution of the Soviet Union, Ukraine inherited a 780,000-man military force on its territory, equipped with the third-largest nuclear weapons arsenal in the world. In May 1992, Ukraine signed the Lisbon Protocol in which the country agreed to give up all nuclear weapons to Russia for disposal and to join the Nuclear Non-Proliferation Treaty as a non-nuclear weapon state. Ukraine ratified the treaty in 1994, and by 1996 the country became free of nuclear weapons.Ukraine took consistent steps toward reduction of conventional weapons. It signed the Treaty on Conventional Armed Forces in Europe, which called for reduction of tanks, artillery, and armoured vehicles (army forces were reduced to 300,000). The country plans to convert the current conscript-based military into a professional volunteer military.

Question: When was Eritrea annexed by the largest troop contributor to the group in which the US and country signing a non-aggression pact with Germany in 1939 became important members?
Answer: 1953