Empires emerge when stronger polities or nation-states dominate weaker ones, typically through military conquest. Though they incorporated many different populations, the ancient empires—Egyptian, Persian, Greek, Roman, Chinese—were, generally speaking, territorially contiguous. But the modern, Western empires that began to form during the Renaissance extended overseas to the Americas, many parts of Asia and Africa, and by the late 1700s to the South Pacific and Australasia. Starting in the late 1400s, the Portuguese and Spanish were first to claim major overseas possessions, followed by the Dutch, French, and English, and eventually by other European nations, including Italy, Belgium, and Germany. Besides these overseas empires, by the 1800s, in Eastern Europe, Western Asia, and North Africa there were three other large empires: Austro-Hungarian, Russian, and Ottoman.

With the Tudor and then Cromwellian invasions of Ireland, England came to dominate its “Celtic fringe,” including also Wales and Scotland. So England had an “internal empire” before it had overseas colonies. And insofar as the English viewed the Irish as a foreign and inferior race, racism arose as an ideological corollary of modern imperialism. All of the nation-states of Europe viewed the inhabitants of the empires they established abroad as their racial inferiors, typically either as “barbarians” or “savages.” Racism then gave rise to one of the standard justifications for imperialism, the so-called “civilizing mission” of the “white man” to rescue the “savages” from their supposedly benighted customs and beliefs. Missionaries such as David Livingstone often were part of the vanguard of empires. Stereotypes about savagery were also fueled by the often fierce resistance that indigenous peoples almost everywhere posed to European invaders. That resistance was usually defeated by Western firepower and diseases to which non-Westerners had little or no immunity. These factors gave rise to the widespread idea that most or even all of the “dark races” of the world were doomed to extinction as the white “race” took over their lands.

Modern racism was strengthened by the slave trade and slavery. Portugal, Spain, France, and Britain all imported slaves from West Africa to work on sugar cane and cotton plantations in the Americas. Meanwhile so-called “scientific racism” developed from Enlightenment natural history, leading to social Darwinism and the eugenics movement of the late nineteenth century. By 1900, the dominant view among Europeans was that most if not all of history could be explained by race warfare, with the so-called “white race” almost always coming out on top. Even within the European context, race conflict seemed to explain history, as in the case of the Norman conquest of England.

Unlike the old term “empire,” “imperialism” is of relatively recent origin, and typically refers either to the process of the formation of empires or to ideological justifications for their existence. Sometimes that process involved colonization, or the establishment of permanent settlements by migrants from the dominant polity or metropole. That was the case with Britain's North American colonies, but not with British India. Both before and after the Indian “mutiny” or rebellion of 1857–58, Britons did not look to establish permanent colonies there. Apart from Algeria and southern Africa, the European powers did not usually seek to establish major colonies in that continent either. Moreover, settler colonialism in the Americas, Australia, and elsewhere often produced genocides against indigenous populations.

In The Expansion of England (1883), Sir J. R. Seeley famously declared, “We seem, as it were, to have conquered and peopled half the world in a fit of absence of mind.”Footnote ¹ To the extent that British imperialism did not dominate British culture before the 1880s, his statement is perhaps accurate. Yet imperial and colonial affairs were of major importance in governance, in the news, in literature and in the arts. The rise of the “new Imperialism” with the so-called “scramble for Africa” starting in 1883 made questions of empire inescapable in Britain and Europe. What was particularly new in the 1880s was the competition among the European nations over most of the portions of the globe that had not yet been incorporated into their empires. That competition included new entries from Belgium (King Leopold's private empire in the Congo), Italy (Libya and Eritrea), and Germany (German East Africa and Southwestern Africa). Meanwhile the expansion of the United States under the aegis of “Manifest Destiny” to the Pacific Ocean and beyond led to most of the planet being incorporated into the Western empires. Yet after World War I those empires began to crumble.

After the American Revolution, Britain came to view most of its other territories of “white settlement” as places that would eventually “mature” into partial independence. Running their own affairs, Canada, Australia, New Zealand, and perhaps even Cape Colony might become loyal members of a “commonwealth” of nations. It was harder to make that case for India and Ireland. The Irish struggle for independence was ongoing and often violent, and—as the Indian Rebellion proved—that was the case also with “the Raj.” Except for Northern Ireland, most of Ireland would break away from English domination by 1921, and India achieved independence by 1948. Decolonization followed in many parts of the world, leading to an era that has been called “postcolonial.”

The freedom struggles of the colonized gave rise to new literatures and ideas about empire and race. In the past, notions of race conflict and the racial superiority of Europeans, often accompanied by the idea of a “civilizing mission,” downplayed the issue of economic exploitation. But the first stage in the creation of modern empires frequently involved the activities of trading companies such as the British East India Company (EIC). To protect its interests both against indigenous resistance and European competitors, the EIC developed an army consisting mainly of Indian troops or sepoys, which eventually led to the British takeover of most of the subcontinent. As Karl Marx, John Hobson, and Vladimir Lenin recognized, in theorizing about empires it is impossible to ignore issues of economic exploitation. And although decolonization may have ended Europe's official political domination of its former colonies, it has not brought economic exploitation to an end. After World War II, the World Bank and the International Monetary Fund were supposed to help the so-called underdeveloped world catch up economically with the West. But rather than achieving a benign condition of globalization and economic progress, while the power and wealth of transnational corporations, based mainly in the West, has grown, poverty throughout much of the world has increased. To call our present era “postcolonial” is therefore misleading. It is more accurate to speak of “neocolonialism,” as Kwame Nkrumah, first president of independent Ghana, did in the 1960s.

Furthermore, after 9/11, the U. S. invasions of Afghanistan and Iraq have demonstrated that military versions of imperialism have not gone away. The approximately 800 military bases the U. S. maintains around the world reinforce its version of economic imperialism via transnational corporate capitalism. Through so-called “free trade” agreements such as NAFTA, the U. S., Britain, and the EU also maintain their worldwide economic domination. Current economic, political, and military practices no doubt differ from those of the past, but they are nevertheless continuations of Western imperialism. The old notions of the “civilizing mission” and of the racial superiority of “the white man” may have given way to ideas about globalization, development, and racial equality. But these merely disguise the growing economic divide between the West and the Rest, and in many places including the U. S., insistence on racial differences and “white supremacy” persist. From the 1400s on, Western imperialism, fueled by capitalist expansion, has been the major factor driving both global modernization and increasing global inequality and poverty. It has also been a major factor underlying many wars and genocides.