Colonialism is the policy of a polity seeking to extend or retain its authority over other people or territories, generally with the aim of developing or exploiting them to the benefit of the colonizing country and of helping the colonies modernize in terms defined by the colonizers, especially in economics, religion, and health.
The European colonial period was the era from the 15th century to 1914 when European states established empires. The Spanish Empire, Portuguese Empire, British Empire, Swedish Empire, French colonial empire, Russian Empire, Dutch Empire, Belgian Congo, Danish colonial empire, German Empire, and Italian Empire established colonies across large areas. The Ottoman Empire, Imperial Japan and the United States also acquired colonies, as did Chinese Imperialism.
At first, European colonizing countries followed policies of mercantilism, in order to strengthen the home economy at the expense of rivals, so regulations usually restricted the colonies to trading only with the metropole (mother country). By the mid-19th century, however, the powerful British Empire gave up mercantilism and trade restrictions and adopted the principle of free trade, with few restrictions or tariffs. Christian missionaries were active in practically all of the colonies. Historian Philip Hoffman calculated that by 1800, before the Industrial Revolution, Europeans already controlled at least 35% of the globe, and by 1914, they had gained control of 84%. The archetypal European colonial system practically ended between 1945–1975, when nearly all Europe's colonies gained political independence.
Collins English Dictionary defines colonialism as "the policy and practice of a power in extending control over weaker peoples or areas". Webster's Encyclopedic Dictionary defines colonialism as "the system or policy of a nation seeking to extend or retain its authority over other people or territories." The Merriam-Webster Dictionary offers four definitions, including "something characteristic of a colony" and "control by one power over a dependent area or people."
The Stanford Encyclopedia of Philosophy "uses the term 'colonialism' to describe the process of European settlement and political control over the rest of the world, including the Americas, Australia, and parts of Africa and Asia". It discusses the distinction between colonialism and imperialism and states that "given the difficulty of consistently distinguishing between the two terms, this entry will use colonialism as a broad concept that refers to the project of European political domination from the sixteenth to the twentieth centuries that ended with the national liberation movements of the 1960s."
In his preface to Jürgen Osterhammel's Colonialism: A Theoretical Overview, Roger Tignor says, "For Osterhammel, the essence of colonialism is the existence of colonies, which are by definition governed differently from other territories such as protectorates or informal spheres of influence." In the book, Osterhammel asks, "How can 'colonialism' be defined independently from 'colony?'" He settles on a three-sentence definition:
Colonialism is a relationship between an indigenous (or forcibly imported) majority and a minority of foreign invaders. The fundamental decisions affecting the lives of the colonized people are made and implemented by the colonial rulers in pursuit of interests that are often defined in a distant metropolis. Rejecting cultural compromises with the colonized population, the colonizers are convinced of their own superiority and their ordained mandate to rule.