Question: When did Christianity become the official religion of the empire that conquered Halford Mackinder's birthplace around AD 43?

full_context: Document 1: 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 2: 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 3: 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.
Document 4: Religion in ancient Rome: Constantine successfully balanced his own role as an instrument of the pax deorum with the power of the Christian priesthoods in determining what was (in traditional Roman terms) auspicious - or in Christian terms, what was orthodox. The edict of Milan (313) redefined Imperial ideology as one of mutual toleration. Constantine had triumphed under the signum (sign) of the Christ: Christianity was therefore officially embraced along with traditional religions and from his new Eastern capital, Constantine could be seen to embody both Christian and Hellenic religious interests. He may have officially ended – or attempted to end – blood sacrifices to the genius of living emperors but his Imperial iconography and court ceremonial outstripped Diocletian's in their supra-human elevation of the Imperial hierarch. His later direct intervention in Church affairs proved a political masterstroke. Constantine united the empire as an absolute head of state, and on his death, he was honored as a Christian, Imperial, and "divus".
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: 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 7: 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 8: State church of the Roman Empire: Nicene Christianity became the state church of the Roman Empire with the Edict of Thessalonica in 380 AD, when Emperor Theodosius I made it the Empire's sole authorized religion. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church each claim to be the historical continuation of this church in its original form, but do not identify with it in the caesaropapist form that it took later. Unlike Constantine I, who with the Edict of Milan of 313 AD had established tolerance for Christianity without placing it above other religions and whose involvement in matters of the Christian faith extended to convoking councils of bishops who were to determine doctrine and to presiding at their meetings, but not to determining doctrine himself, Theodosius established a single Christian doctrine (specified as that professed by Pope Damasus I of Rome and Pope Peter II of Alexandria) as the Empire's official religion.
Document 9: Diocletianic Persecution: The Diocletianic or Great Persecution was the last and most severe persecution of Christians in the Roman Empire. In 303, the Emperors Diocletian, Maximian, Galerius, and Constantius issued a series of edicts rescinding the legal rights of Christians and demanding that they comply with traditional Roman religious practices. Later edicts targeted the clergy and ordered all inhabitants to sacrifice to the Roman gods (a policy known as universal sacrifice). The persecution varied in intensity across the empire -- weakest in Gaul and Britain, where only the first edict was applied, and strongest in the Eastern provinces. Persecutory laws were nullified by different emperors at different times, but Constantine and Licinius's Edict of Milan (313) has traditionally marked the end of the persecution.
Document 10: 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 11: Constantine the Great and Christianity: Constantine's decision to cease the persecution of Christians in the Roman Empire was a turning point for early Christianity, sometimes referred to as the Triumph of the Church, the Peace of the Church or the Constantinian shift. In 313, Constantine and Licinius issued the Edict of Milan decriminalizing Christian worship. The emperor became a great patron of the Church and set a precedent for the position of the Christian emperor within the Church and the notion of orthodoxy, Christendom, ecumenical councils, and the state church of the Roman Empire declared by edict in 380. He is revered as a saint and isapostolos in the Eastern Orthodox Church, Oriental Orthodox Church, and various Eastern Catholic Churches for his example as a ``Christian monarch. ''
Document 12: 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 13: 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 14: 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 15: Constantine the Great and Christianity: During the reign of the Roman Emperor Constantine the Great (306 -- 337 AD), Christianity began to transition to the dominant religion of the Roman Empire. Historians remain uncertain about Constantine's reasons for favoring Christianity, and theologians and historians have often argued about which form of Early Christianity he subscribed to. There is no consensus among scholars as to whether he adopted his mother Helena's Christianity in his youth, or, as claimed by Eusebius, encouraged her to convert to the faith himself. Some scholars question the extent to which he should be considered a Christian emperor: ``Constantine saw himself as an 'emperor of the Christian people'. If this made him a Christian is the subject of... debate, ''although he allegedly received a baptism shortly before his death.
ground_truth: 380
sub_queries: Where was Halford Mackinder born? Answer: Britain
Who foreign group conquered Britain around AD 43? Answer: Roman Empire
christianity become the official religion of Roman Empire in Answer: 380