Question: When did the foreign group who conquered Halford Mackinder's birthplace begin to fall?

full_context: Document 1: British Isles: Viking invasions began in the 9th century, followed by more permanent settlements, particularly along the east coast of Ireland, the west coast of modern-day Scotland and the Isle of Man. Though the Vikings were eventually neutralised in Ireland, their influence remained in the cities of Dublin, Cork, Limerick, Waterford and Wexford. England however was slowly conquered around the turn of the first millennium AD, and eventually became a feudal possession of Denmark. The relations between the descendants of Vikings in England and counterparts in Normandy, in northern France, lay at the heart of a series of events that led to the Norman conquest of England in 1066. The remnants of the Duchy of Normandy, which conquered England, remain associated to the English Crown as the Channel Islands to this day. A century later the marriage of the future Henry II of England to Eleanor of Aquitaine created the Angevin Empire, partially under the French Crown. At the invitation of a provincial king and under the authority of Pope Adrian IV (the only Englishman to be elected pope), the Angevins invaded Ireland in 1169. Though initially intended to be kept as an independent kingdom, the failure of the Irish High King to ensure the terms of the Treaty of Windsor led Henry II, as King of England, to rule as effective monarch under the title of Lord of Ireland. This title was granted to his younger son but when Henry's heir unexpectedly died the title of King of England and Lord of Ireland became entwined in one person.
Document 2: Imperialism: The correlation between capitalism, aristocracy, and imperialism has long been debated among historians and political theorists. Much of the debate was pioneered by such theorists as J. A. Hobson (1858–1940), Joseph Schumpeter (1883–1950), Thorstein Veblen (1857–1929), and Norman Angell (1872–1967). While these non-Marxist writers were at their most prolific before World War I, they remained active in the interwar years. Their combined work informed the study of imperialism and it's impact on Europe, as well as contributed to reflections on the rise of the military-political complex in the United States from the 1950s. Hobson argued that domestic social reforms could cure the international disease of imperialism by removing its economic foundation. Hobson theorized that state intervention through taxation could boost broader consumption, create wealth, and encourage a peaceful, tolerant, multipolar world order.
Document 3: Imperialism: A resurgence came in the late 19th century, with the Scramble for Africa and major additions in Asia and the Middle East. The British spirit of imperialism was expressed by Joseph Chamberlain and Lord Rosebury, and implemented in Africa by Cecil Rhodes. The pseudo-sciences of Social Darwinism and theories of race formed an ideological underpinning during this time. Other influential spokesmen included Lord Cromer, Lord Curzon, General Kitchner, Lord Milner, and the writer Rudyard Kipling. The British Empire was the largest Empire that the world has ever seen both in terms of landmass and population. Its power, both military and economic, remained unmatched.
Document 4: Southern Europe: The Roman Empire came to dominate the entire Mediterranean basin in a vast empire based on Roman law and Roman legions. It promoted trade, tolerance, and Greek culture. By 300 AD the Roman Empire was divided into the Western Roman Empire based in Rome, and the Eastern Roman Empire based in Constantinople. The attacks of the Germanic peoples of northern Europe led to the Fall of the Western Roman Empire in AD 476, a date which traditionally marks the end of the classical period and the start of the Middle Ages.
Document 5: British Isles: Anglo-Saxons arrived as Roman power waned in the 5th century AD. Initially, their arrival seems to have been at the invitation of the Britons as mercenaries to repulse incursions by the Hiberni and Picts. In time, Anglo-Saxon demands on the British became so great that they came to culturally dominate the bulk of southern Great Britain, though recent genetic evidence suggests Britons still formed the bulk of the population. This dominance creating what is now England and leaving culturally British enclaves only in the north of what is now England, in Cornwall and what is now known as Wales. Ireland had been unaffected by the Romans except, significantly, having been Christianised, traditionally by the Romano-Briton, Saint Patrick. As Europe, including Britain, descended into turmoil following the collapse of Roman civilisation, an era known as the Dark Ages, Ireland entered a golden age and responded with missions (first to Great Britain and then to the continent), the founding of monasteries and universities. These were later joined by Anglo-Saxon missions of a similar nature.
Document 6: East–West Schism: In 476, when the last emperor of the western part of the Roman Empire was deposed and the western imperial insignia were sent to Constantinople, there was once again a single Roman Emperor. However, he had little power in the West, which was ruled almost entirely by various Germanic tribes. In the opinion of Randall R. Cloud, the permanent separation of the Greek East from the Latin West was ``the fundamental reason for the estrangement that soon followed between the Greek and the Latin Christians ''.
Document 7: Near East: It has pleased western historians to write of a decline of the Ottoman Empire as though a stable and uncontested polity of that name once existed. The borders did expand and contract but they were always dynamic and always in "question" right from the beginning. The Ottoman Empire was created from the lands of the former eastern Roman Empire on the occasion of the latter's violent demise. The last Roman emperor died fighting hand-to-hand in the streets of his capital, Constantinople, overwhelmed by the Ottoman military, in May, 1453. The victors inherited his remaining territory in the Balkans.
Document 8: Imperialism: To better illustrate this idea, Bassett focuses his analysis of the role of nineteenth-century maps during the "scramble for Africa". He states that maps "contributed to empire by promoting, assisting, and legitimizing the extension of French and British power into West Africa". During his analysis of nineteenth-century cartographic techniques, he highlights the use of blank space to denote unknown or unexplored territory. This provided incentives for imperial and colonial powers to obtain "information to fill in blank spaces on contemporary maps".
Document 9: British Isles: At the time of the Roman Empire, about two thousand years ago, various tribes, which spoke Celtic dialects of the Insular Celtic group, were inhabiting the islands. The Romans expanded their civilisation to control southern Great Britain but were impeded in advancing any further, building Hadrian's Wall to mark the northern frontier of their empire in 122 AD. At that time, Ireland was populated by a people known as Hiberni, the northern third or so of Great Britain by a people known as Picts and the southern two thirds by Britons.
Document 10: Imperialism: During the 20th century, historians John Gallagher (1919–1980) and Ronald Robinson (1920–1999) constructed a framework for understanding European imperialism. They claim that European imperialism was influential, and Europeans rejected the notion that "imperialism" required formal, legal control by one government over another country. "In their view, historians have been mesmerized by formal empire and maps of the world with regions colored red. The bulk of British emigration, trade, and capital went to areas outside the formal British Empire. Key to their thinking is the idea of empire 'informally if possible and formally if necessary.'"[attribution needed] Because of the resources made available by imperialism, the world's economy grew significantly and became much more interconnected in the decades before World War I, making the many imperial powers rich and prosperous.
Document 11: British Isles: The Kingdoms of England and Scotland were unified in 1707 creating the Kingdom of Great Britain. Following an attempted republican revolution in Ireland in 1798, the Kingdoms of Ireland and Great Britain were unified in 1801, creating the United Kingdom. The Isle of Man and the Channel Islands remaining outside of the United Kingdom but with their ultimate good governance being the responsibility of the British Crown (effectively the British government). Although, the colonies of North American that would become the United States of America were lost by the start of the 19th century, the British Empire expanded rapidly elsewhere. A century later it would cover one third of the globe. Poverty in the United Kingdom remained desperate however and industrialisation in England led to terrible condition for the working class. Mass migrations following the Irish Famine and Highland Clearances resulted in the distribution of the islands' population and culture throughout the world and a rapid de-population of Ireland in the second-half of the 19th century. Most of Ireland seceded from the United Kingdom after the Irish War of Independence and the subsequent Anglo-Irish Treaty (1919–1922), with the six counties that formed Northern Ireland remaining as an autonomous region of the UK.
Document 12: Fall of the Western Roman Empire: Relevant dates include 117 CE, when the Empire was at its greatest territorial extent, and the accession of Diocletian in 284. Irreversible major territorial loss, however, began in 376 with a large - scale irruption of Goths and others. In 395, after winning two destructive civil wars, Theodosius I died, leaving a collapsing field army and the Empire, still plagued by Goths, divided between his two incapable sons. By 476 when Odoacer deposed the Emperor Romulus, the Western Roman Emperor wielded negligible military, political, or financial power and had no effective control over the scattered Western domains that could still be described as Roman. Invading barbarians had established their own power in most of the area of the Western Empire. While its legitimacy lasted for centuries longer and its cultural influence remains today, the Western Empire never had the strength to rise again.
Document 13: Middle Ages: The Emperor Diocletian (r. 284–305) split the empire into separately administered eastern and western halves in 286; the empire was not considered divided by its inhabitants or rulers, as legal and administrative promulgations in one division were considered valid in the other.[C] In 330, after a period of civil war, Constantine the Great (r. 306–337) refounded the city of Byzantium as the newly renamed eastern capital, Constantinople. Diocletian's reforms strengthened the governmental bureaucracy, reformed taxation, and strengthened the army, which bought the empire time but did not resolve the problems it was facing: excessive taxation, a declining birthrate, and pressures on its frontiers, among others. Civil war between rival emperors became common in the middle of the 4th century, diverting soldiers from the empire's frontier forces and allowing invaders to encroach. For much of the 4th century, Roman society stabilised in a new form that differed from the earlier classical period, with a widening gulf between the rich and poor, and a decline in the vitality of the smaller towns. Another change was the Christianisation, or conversion of the empire to Christianity, a gradual process that lasted from the 2nd to the 5th centuries.
Document 14: Imperialism: The Royal Geographical Society of London and other geographical societies in Europe had great influence and were able to fund travelers who would come back with tales of their discoveries. These societies also served as a space for travellers to share these stories.Political geographers such as Friedrich Ratzel of Germany and Halford Mackinder of Britain also supported imperialism. Ratzel believed expansion was necessary for a state’s survival while Mackinder supported Britain’s imperial expansion; these two arguments dominated the discipline for decades.
Document 15: British Isles: Hiberni (Ireland), Pictish (northern Britain) and Britons (southern Britain) tribes, all speaking Insular Celtic, inhabited the islands at the beginning of the 1st millennium AD. Much of Brittonic-controlled Britain was conquered by the Roman Empire from AD 43. The first Anglo-Saxons arrived as Roman power waned in the 5th century and eventually dominated the bulk of what is now England. Viking invasions began in the 9th century, followed by more permanent settlements and political change—particularly in England. The subsequent Norman conquest of England in 1066 and the later Angevin partial conquest of Ireland from 1169 led to the imposition of a new Norman ruling elite across much of Britain and parts of Ireland. By the Late Middle Ages, Great Britain was separated into the Kingdoms of England and Scotland, while control in Ireland fluxed between Gaelic kingdoms, Hiberno-Norman lords and the English-dominated Lordship of Ireland, soon restricted only to The Pale. The 1603 Union of the Crowns, Acts of Union 1707 and Acts of Union 1800 attempted to consolidate Britain and Ireland into a single political unit, the United Kingdom of Great Britain and Ireland, with the Isle of Man and the Channel Islands remaining as Crown Dependencies. The expansion of the British Empire and migrations following the Irish Famine and Highland Clearances resulted in the distribution of the islands' population and culture throughout the world and a rapid de-population of Ireland in the second half of the 19th century. Most of Ireland seceded from the United Kingdom after the Irish War of Independence and the subsequent Anglo-Irish Treaty (1919–1922), with six counties remaining in the UK as Northern Ireland.
ground_truth: in 376
sub_queries: Where was Halford Mackinder born? Answer: Britain
Who foreign group conquered Britain around AD 43? Answer: Roman Empire
when did Roman Empire began to fall Answer: in 376