Question: When did Britain withdraw from the place which was the central point of pearl trading?

full_context: Document 1: Hellenistic period: The Nabatean Kingdom was an Arab state located between the Sinai Peninsula and the Arabian Peninsula. Its capital was the city of Petra, an important trading city on the incense route. The Nabateans resisted the attacks of Antigonous and were allies of the Hasmoneans in their struggle against the Seleucids, but later fought against Herod the great. The hellenization of the Nabateans accured relatively late in comparison to the surrounding regions. Nabatean material culture does not show any Greek influence until the reign of Aretas III Philhellene in the 1st century BCE. Aretas captured Damascus and built the Petra pool complex and gardens in the Hellenistic style. Though the Nabateans originally worshipped their traditional gods in symbolic form such as stone blocks or pillars, during the Hellenistic period they began to identify their gods with Greek gods and depict them in figurative forms influenced by Greek sculpture. Nabatean art shows Greek influences and paintings have been found depicting Dionysian scenes. They also slowly adopted Greek as a language of commerce along with Aramaic and Arabic.
Document 2: Greeks: In ancient times, the trading and colonizing activities of the Greek tribes and city states spread the Greek culture, religion and language around the Mediterranean and Black Sea basins, especially in Sicily and southern Italy (also known as Magna Grecia), Spain, the south of France and the Black sea coasts. Under Alexander the Great's empire and successor states, Greek and Hellenizing ruling classes were established in the Middle East, India and in Egypt. The Hellenistic period is characterized by a new wave of Greek colonization that established Greek cities and kingdoms in Asia and Africa. Under the Roman Empire, easier movement of people spread Greeks across the Empire and in the eastern territories, Greek became the lingua franca rather than Latin. The modern-day Griko community of southern Italy, numbering about 60,000, may represent a living remnant of the ancient Greek populations of Italy.
Document 3: British Empire: In 1951, the Conservative Party returned to power in Britain, under the leadership of Winston Churchill. Churchill and the Conservatives believed that Britain's position as a world power relied on the continued existence of the empire, with the base at the Suez Canal allowing Britain to maintain its pre-eminent position in the Middle East in spite of the loss of India. However, Churchill could not ignore Gamal Abdul Nasser's new revolutionary government of Egypt that had taken power in 1952, and the following year it was agreed that British troops would withdraw from the Suez Canal zone and that Sudan would be granted self-determination by 1955, with independence to follow. Sudan was granted independence on 1 January 1956.
Document 4: Greeks: Greek colonies and communities have been historically established on the shores of the Mediterranean Sea and Black Sea, but the Greek people have always been centered around the Aegean and Ionian seas, where the Greek language has been spoken since the Bronze Age. Until the early 20th century, Greeks were distributed between the Greek peninsula, the western coast of Asia Minor, the Black Sea coast, Cappadocia in central Anatolia, Egypt, the Balkans, Cyprus, and Constantinople. Many of these regions coincided to a large extent with the borders of the Byzantine Empire of the late 11th century and the Eastern Mediterranean areas of ancient Greek colonization. The cultural centers of the Greeks have included Athens, Thessalonica, Alexandria, Smyrna, and Constantinople at various periods.
Document 5: Hellenistic period: The identification of local gods with similar Greek deities, a practice termed 'Interpretatio graeca', facilitated the building of Greek-style temples, and the Greek culture in the cities also meant that buildings such as gymnasia and theaters became common. Many cities maintained nominal autonomy while under the rule of the local king or satrap, and often had Greek-style institutions. Greek dedications, statues, architecture and inscriptions have all been found. However, local cultures were not replaced, and mostly went on as before, but now with a new Greco-Macedonian or otherwise Hellenized elite. An example that shows the spread of Greek theater is Plutarch's story of the death of Crassus, in which his head was taken to the Parthian court and used as a prop in a performance of The Bacchae. Theaters have also been found: for example, in Ai-Khanoum on the edge of Bactria, the theater has 35 rows – larger than the theater in Babylon.
Document 6: British Empire: The Suez Crisis very publicly exposed Britain's limitations to the world and confirmed Britain's decline on the world stage, demonstrating that henceforth it could no longer act without at least the acquiescence, if not the full support, of the United States. The events at Suez wounded British national pride, leading one MP to describe it as "Britain's Waterloo" and another to suggest that the country had become an "American satellite". Margaret Thatcher later described the mindset she believed had befallen the British political establishment as "Suez syndrome", from which Britain did not recover until the successful recapture of the Falkland Islands from Argentina in 1982.
Document 7: British Empire: In July 1956, Nasser unilaterally nationalised the Suez Canal. The response of Anthony Eden, who had succeeded Churchill as Prime Minister, was to collude with France to engineer an Israeli attack on Egypt that would give Britain and France an excuse to intervene militarily and retake the canal. Eden infuriated US President Dwight D. Eisenhower, by his lack of consultation, and Eisenhower refused to back the invasion. Another of Eisenhower's concerns was the possibility of a wider war with the Soviet Union after it threatened to intervene on the Egyptian side. Eisenhower applied financial leverage by threatening to sell US reserves of the British pound and thereby precipitate a collapse of the British currency. Though the invasion force was militarily successful in its objectives, UN intervention and US pressure forced Britain into a humiliating withdrawal of its forces, and Eden resigned.
Document 8: Hellenistic period: After Alexander the Great's ventures in the Persian Empire, Hellenistic kingdoms were established throughout south-west Asia (Seleucid Empire, Kingdom of Pergamon), north-east Africa (Ptolemaic Kingdom) and South Asia (Greco-Bactrian Kingdom, Indo-Greek Kingdom). This resulted in the export of Greek culture and language to these new realms through Greco-Macedonian colonization, spanning as far as modern-day Pakistan. Equally, however, these new kingdoms were influenced by the indigenous cultures, adopting local practices where beneficial, necessary, or convenient. Hellenistic culture thus represents a fusion of the Ancient Greek world with that of the Near East, Middle East, and Southwest Asia, and a departure from earlier Greek attitudes towards "barbarian" cultures. The Hellenistic period was characterized by a new wave of Greek colonization (as distinguished from that occurring in the 8th–6th centuries BC) which established Greek cities and kingdoms in Asia and Africa. Those new cities were composed of Greek colonists who came from different parts of the Greek world, and not, as before, from a specific "mother city". The main cultural centers expanded from mainland Greece to Pergamon, Rhodes, and new Greek colonies such as Seleucia, Antioch, Alexandria and Ai-Khanoum. This mixture of Greek-speakers gave birth to a common Attic-based dialect, known as Koine Greek, which became the lingua franca through the Hellenistic world.
Document 9: British Empire: Though Britain and the empire emerged victorious from the Second World War, the effects of the conflict were profound, both at home and abroad. Much of Europe, a continent that had dominated the world for several centuries, was in ruins, and host to the armies of the United States and the Soviet Union, who now held the balance of global power. Britain was left essentially bankrupt, with insolvency only averted in 1946 after the negotiation of a $US 4.33 billion loan from the United States, the last instalment of which was repaid in 2006. At the same time, anti-colonial movements were on the rise in the colonies of European nations. The situation was complicated further by the increasing Cold War rivalry of the United States and the Soviet Union. In principle, both nations were opposed to European colonialism. In practice, however, American anti-communism prevailed over anti-imperialism, and therefore the United States supported the continued existence of the British Empire to keep Communist expansion in check. The "wind of change" ultimately meant that the British Empire's days were numbered, and on the whole, Britain adopted a policy of peaceful disengagement from its colonies once stable, non-Communist governments were established to assume power. This was in contrast to other European powers such as France and Portugal, which waged costly and ultimately unsuccessful wars to keep their empires intact. Between 1945 and 1965, the number of people under British rule outside the UK itself fell from 700 million to five million, three million of whom were in Hong Kong.
Document 10: Overseas military bases of the United Kingdom: The United Kingdom is still considered and remains a global power even into the 21st century; this is evidenced through the nation's 15 overseas military bases, making it second only to the United States in terms of total overseas bases worldwide. Currently, there is also the possibility of an additional two new bases being built in Oman and the United Arab Emirates in the near future. Note that both the United Arab Emirates and Oman were once under British rule, showing the impact of colonialism and the British armed forces military presence across the globe, even into the 21st century.
Document 11: Hellenistic period: It seems likely that Alexander himself pursued policies which led Hellenization, such as the foundations of new cities and Greek colonies. While it may have been a deliberate attempt to spread Greek culture (or as Arrian says, "to civilise the natives"), it is more likely that it was a series of pragmatic measures designed to aid in the rule of his enormous empire. Cities and colonies were centers of administrative control and Macedonian power in a newly conquered region. Alexander also seems to have attempted to create a mixed Greco-Persian elite class as shown by the Susa weddings and his adoption of some forms of Persian dress and court culture. He also brought in Persian and other non-Greek peoples into his military and even the elite cavalry units of the companion cavalry. Again, it is probably better to see these policies as a pragmatic response to the demands of ruling a large empire than to any idealized attempt to bringing Greek culture to the 'barbarians'. This approach was bitterly resented by the Macedonians and discarded by most of the Diadochi after Alexander's death. These policies can also be interpreted as the result of Alexander's possible megalomania during his later years.
Document 12: Hellenistic period: In Arabia, Bahrain, which was referred to by the Greeks as Tylos, the centre of pearl trading, when Nearchus came to discover it serving under Alexander the Great. The Greek admiral Nearchus is believed to have been the first of Alexander's commanders to visit these islands. It is not known whether Bahrain was part of the Seleucid Empire, although the archaeological site at Qalat Al Bahrain has been proposed as a Seleucid base in the Persian Gulf. Alexander had planned to settle the eastern shores of the Persian Gulf with Greek colonists, and although it is not clear that this happened on the scale he envisaged, Tylos was very much part of the Hellenised world: the language of the upper classes was Greek (although Aramaic was in everyday use), while Zeus was worshipped in the form of the Arabian sun-god Shams. Tylos even became the site of Greek athletic contests.
Document 13: Elizabeth II: In 1956, the British and French prime ministers, Sir Anthony Eden and Guy Mollet, discussed the possibility of France joining the Commonwealth. The proposal was never accepted and the following year France signed the Treaty of Rome, which established the European Economic Community, the precursor to the European Union. In November 1956, Britain and France invaded Egypt in an ultimately unsuccessful attempt to capture the Suez Canal. Lord Mountbatten claimed the Queen was opposed to the invasion, though Eden denied it. Eden resigned two months later.
Document 14: British Empire: Though Britain and the empire emerged victorious from the Second World War, the effects of the conflict were profound, both at home and abroad. Much of Europe, a continent that had dominated the world for several centuries, was in ruins, and host to the armies of the United States and the Soviet Union, who now held the balance of global power. Britain was left essentially bankrupt, with insolvency only averted in 1946 after the negotiation of a $US 4.33 billion loan (US$56 billion in 2012) from the United States, the last instalment of which was repaid in 2006. At the same time, anti-colonial movements were on the rise in the colonies of European nations. The situation was complicated further by the increasing Cold War rivalry of the United States and the Soviet Union. In principle, both nations were opposed to European colonialism. In practice, however, American anti-communism prevailed over anti-imperialism, and therefore the United States supported the continued existence of the British Empire to keep Communist expansion in check. The "wind of change" ultimately meant that the British Empire's days were numbered, and on the whole, Britain adopted a policy of peaceful disengagement from its colonies once stable, non-Communist governments were available to transfer power to. This was in contrast to other European powers such as France and Portugal, which waged costly and ultimately unsuccessful wars to keep their empires intact. Between 1945 and 1965, the number of people under British rule outside the UK itself fell from 700 million to five million, three million of whom were in Hong Kong.
Document 15: British Empire: While the Suez Crisis caused British power in the Middle East to weaken, it did not collapse. Britain again deployed its armed forces to the region, intervening in Oman (1957), Jordan (1958) and Kuwait (1961), though on these occasions with American approval, as the new Prime Minister Harold Macmillan's foreign policy was to remain firmly aligned with the United States. Britain maintained a military presence in the Middle East for another decade. In January 1968, a few weeks after the devaluation of the pound, Prime Minister Harold Wilson and his Defence Secretary Denis Healey announced that British troops would be withdrawn from major military bases East of Suez, which included the ones in the Middle East, and primarily from Malaysia and Singapore. The British withdrew from Aden in 1967, Bahrain in 1971, and Maldives in 1976.
ground_truth: 1971
sub_queries: Where was the central point of pearl trading? Answer: Bahrain
When did Britain withdraw from Bahrain ? Answer: 1971