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?

full_context: Document 1: Molotov–Ribbentrop Pact: On August 19, the 1939 German–Soviet Commercial Agreement was finally signed. On 21 August, the Soviets suspended Tripartite military talks, citing other reasons. That same day, Stalin received assurance that Germany would approve secret protocols to the proposed non-aggression pact that would place half of Poland (border along the Vistula river), Latvia, Estonia, Finland, and Bessarabia in the Soviets' sphere of influence. That night, Stalin replied that the Soviets were willing to sign the pact and that he would receive Ribbentrop on 23 August.
Document 2: List of members of the United Nations Security Council: As of July 2011, there are currently 193 members of the United Nations and five permanent members of the Security Council. The other ten seats are assigned amongst the remaining 188 members. As a result, many members have never been on the Security Council. The following list is a summary of all countries, currently 68 modern nations and three historical ones, that have never been a member of the United Nations Security Council. The three historical UN members listed are Tanganyika, Zanzibar, and the Federal Republic of Yugoslavia.
Document 3: Molotov–Ribbentrop Pact: The Molotov -- Ribbentrop Pact, also known as the Nazi -- Soviet Pact, the German -- Soviet Non-aggression Pact or the Nazi German - Soviet Pact of Aggression (officially: Treaty of Non-aggression between Germany and the Union of Soviet Socialist Republics), was a neutrality pact between Nazi Germany and the Soviet Union signed in Moscow on 23 August 1939 by foreign ministers Joachim von Ribbentrop and Vyacheslav Molotov, respectively. The pact was followed by the German - Soviet Commercial Agreement in February 1940.
Document 4: Eritrea: During the Middle Ages, the Eritrea region was known as Medri Bahri ("sea-land"). The name Eritrea is derived from the ancient Greek name for Red Sea (Ἐρυθρὰ Θάλασσα Erythra Thalassa, based on the adjective ἐρυθρός erythros "red"). It was first formally adopted in 1890, with the formation of Italian Eritrea (Colonia Eritrea). The territory became the Eritrea Governorate within Italian East Africa in 1936. Eritrea was annexed by Ethiopia in 1953 (nominally within a federation until 1962) and an Eritrean Liberation Front formed in 1960. Eritrea gained independence following the 1993 referendum, and the name of the new state was defined as State of Eritrea in the 1997 constitution.[citation needed]
Document 5: Eritrea: The creation of modern-day Eritrea is a result of the incorporation of independent, distinct kingdoms and sultanates (for example, Medri Bahri and the Sultanate of Aussa) eventually resulting in the formation of Italian Eritrea. In 1947 Eritrea became part of a federation with Ethiopia, the Federation of Ethiopia and Eritrea. Subsequent annexation into Ethiopia led to the Eritrean War of Independence, ending with Eritrean independence following a referendum in April 1993. Hostilities between Eritrea and Ethiopia persisted, leading to the Eritrean–Ethiopian War of 1998–2000 and further skirmishes with both Djibouti and Ethiopia.
Document 6: Molotov–Ribbentrop Pact: The Molotov -- Ribbentrop Pact, also known as the Nazi -- Soviet Pact, the German -- Soviet Non-aggression Pact or the Nazi German -- Soviet Pact of Aggression (officially: Treaty of Non-aggression between Germany and the Union of Soviet Socialist Republics), was a neutrality pact between Nazi Germany and the Soviet Union signed in Moscow on 23 August 1939 by foreign ministers Joachim von Ribbentrop and Vyacheslav Molotov, respectively. The pact was followed by the German - Soviet Commercial Agreement in February 1940.
Document 7: United Nations Population Fund: In response, the EU decided to fill the gap left behind by the US under the Sandbaek report. According to its Annual Report for 2008, the UNFPA received its funding mainly from European Governments: Of the total income of M845.3 M, $118 was donated by the Netherlands, $67 M by Sweden, $62 M by Norway, $54 M by Denmark, $53 M by the UK, $52 M by Spain, $19 M by Luxembourg. The European Commission donated further $36 M. The most important non-European donor State was Japan ($36 M). The number of donors exceeded 180 in one year.
Document 8: Modern history: It is possible that around 62 million people died in the war; estimates vary greatly. About 60% of all casualties were civilians, who died as a result of disease, starvation, genocide (in particular, the Holocaust), and aerial bombing. The former Soviet Union and China suffered the most casualties. Estimates place deaths in the Soviet Union at around 23 million, while China suffered about 10 million. No country lost a greater portion of its population than Poland: approximately 5.6 million, or 16%, of its pre-war population of 34.8 million died.
Document 9: United Nations peacekeeping: As of 29 February 2016, 124 countries were contributing a total of 105,314 personnel in Peacekeeping Operations, with Ethiopia leading the tally (8,324), followed by India (7,695) and Bangladesh (7,525). In June 2013. Pakistan contributed the highest number overall with 8,186 personnel, followed by India (7,878), Bangladesh (7,799), Ethiopia (6,502), Rwanda (4,686), Nigeria (4,684), Nepal (4,495), Jordan (3,374), Ghana (2,859), and Egypt (2,750). As of 28 February 2015, 120 countries were contributing a total of 104,928 personnel in Peacekeeping Operations, with Bangladesh leading the tally (9446). As of March 2008, in addition to military and police personnel, 5,187 international civilian personnel, 2,031 UN Volunteers and 12,036 local civilian personnel worked in UN peacekeeping missions.
Document 10: Eritrea: The Scottish traveler James Bruce reported in 1770 that Medri Bahri was a distinct political entity from Abyssinia, noting that the two territories were frequently in conflict. The Bahre-Nagassi ("Kings of the Sea") alternately fought with or against the Abyssinians and the neighbouring Muslim Adal Sultanate depending on the geopolitical circumstances. Medri Bahri was thus part of the Christian resistance against Imam Ahmad ibn Ibrahim al-Ghazi of Adal's forces, but later joined the Adalite states and the Ottoman Empire front against Abyssinia in 1572. That 16th century also marked the arrival of the Ottomans, who began making inroads in the Red Sea area.
Document 11: Soviet Union: The Soviet Union suffered greatly in the war, losing around 27 million people. Approximately 2.8 million Soviet POWs died of starvation, mistreatment, or executions in just eight months of 1941 -- 42. During the war, the Soviet Union together with the United States, the United Kingdom and China were considered as the Big Four of Allied powers in World War II and later became the Four Policemen which was the foundation of the United Nations Security Council. It emerged as a superpower in the post-war period. Once denied diplomatic recognition by the Western world, the Soviet Union had official relations with practically every nation by the late 1940s. A member of the United Nations at its foundation in 1945, the Soviet Union became one of the five permanent members of the United Nations Security Council, which gave it the right to veto any of its resolutions.
Document 12: United Nations Population Fund: Contributions from governments and the private sector to UNFPA in 2014 exceeded $1 billion. The amount includes $477 million to the organization’s core resources and $529 million earmarked for specific programs and initiatives.
Document 13: Eritrea: Eritrea (/ˌɛrᵻˈtreɪ.ə/ or /ˌɛrᵻˈtriːə/;, officially the State of Eritrea, is a country in East Africa. With its capital at Asmara, it is bordered by Sudan in the west, Ethiopia in the south, and Djibouti in the southeast. The northeastern and eastern parts of Eritrea have an extensive coastline along the Red Sea. The nation has a total area of approximately 117,600 km2 (45,406 sq mi), and includes the Dahlak Archipelago and several of the Hanish Islands. Its name Eritrea is based on the Greek name for the Red Sea (Ἐρυθρὰ Θάλασσα Erythra Thalassa), which was first adopted for Italian Eritrea in 1890.
Document 14: Molotov–Ribbentrop Pact: The stated clauses of the Nazi-Soviet non-aggression pact were a guarantee of non-belligerence by each party towards the other, and a written commitment that neither party would ally itself to, or aid, an enemy of the other party. In addition to stipulations of non-aggression, the treaty included a secret protocol that divided territories of Romania, Poland, Lithuania, Latvia, Estonia, and Finland into German and Soviet "spheres of influence", anticipating potential "territorial and political rearrangements" of these countries. Thereafter, Germany invaded Poland on 1 September 1939. After the Soviet–Japanese ceasefire agreement took effect on 16 September, Stalin ordered his own invasion of Poland on 17 September. Part of southeastern (Karelia) and Salla region in Finland were annexed by the Soviet Union after the Winter War. This was followed by Soviet annexations of Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region). Concern about ethnic Ukrainians and Belarusians had been proffered as justification for the Soviet invasion of Poland. Stalin's invasion of Bukovina in 1940 violated the pact, as it went beyond the Soviet sphere of influence agreed with the Axis.
Document 15: Great power: When World War II started in 1939, it divided the world into two alliances—the Allies (the United Kingdom and France at first in Europe, China in Asia since 1937, followed in 1941 by the Soviet Union, the United States); and the Axis powers consisting of Germany, Italy and Japan.[nb 1] During World War II, the United States, United Kingdom, and Soviet Union controlled Allied policy and emerged as the "Big Three". The Republic of China and the Big Three were referred as a "trusteeship of the powerful"  and were recognized as the Allied "Big Four" in Declaration by United Nations in 1942. These four countries were referred as the "Four Policemen" of the Allies and considered as the primary victors of World War II. The importance of France was acknowledged by their inclusion, along with the other four, in the group of countries allotted permanent seats in the United Nations Security Council.
ground_truth: 1953
sub_queries: in 1939 germany agreed to sign a non-aggression pact with which country Answer: the Soviet Union
the us and the Soviet Union became important members in Answer: the United Nations
largest troop contributor to the the United Nations peace keeping mission Answer: Ethiopia
When was Eritrea annexed by Ethiopia ? Answer: 1953