The historical phenomenon of colonisation is one that stretches around the globe and across time, including such disparate peoples as the Hittites, the Incas and the British, although the term colonialism is normally used with reference to European overseas empires rather than land-based empires, European or otherwise, which are better described by the term imperialism. Examples of land-based empires include the Mongol Empire, a large empire stretching from the Western Pacific to Eastern Europe, the Empire of Alexander the Great, the Umayyad Caliphate, the Persian Empire, the Roman Empire, the Byzantine Empire. The Ottoman Empire was created across Mediterranean, North Africa and into Southern Europe and existed during the time of European colonization of the other parts of the world.

European colonialism began in the fifteenth century with the "Age of Discovery", led by Spanish and Portuguese exploration of the Americas, and the coasts of Africa, the Middle East, India, and East Asia. During the sixteenth and seventeenth centuries, England, France and Holland established their own overseas empires, in direct competition with each other. The end of the eighteenth and early nineteenth century saw the first era of decolonization when most of the European colonies in the Americas gained their independence from their respective metropoles. Spain and Portugal were irreversibly weakened after the loss of their New World colonies, but Britain (after the union of England and Scotland), France and Holland turned their attention to the Old World, particularly South Africa, India and South East Asia, where coastal enclaves had already been established. The industrialization of the nineteenth century led to what has been termed the era of New Imperialism, when the pace of colonization rapidly accelerated, the height of which was the Scramble for Africa. During the twentieth century, the overseas colonies of the losers of World War I were distributed amongst the victors as mandates, but it was not until the end of World War II that the second phase of decolonization began in earnest. In 1999 Portugal returned the last of Europe's colonies in Asia, Macau, to China, ending an era that had lasted five hundred years.