Decolonization (or decolonisation) is the undoing of colonialism, where a nation establishes and maintains dependent territory (courial governments). The Oxford English Dictionary defines decolonization as "the withdrawal from its colonies of a colonial power; the acquisition of political or economic independence by such colonies." It can be understood politically (attaining independence, autonomous home rule, union with the metropole or another state) or culturally (removal of pernicious colonial effects.) The term refers particularly to the dismantlement, in the years after World War II, of the colonial empires established prior to World War I throughout the world.The United Nations Special Committee on Decolonization has stated that in the process of decolonization there is no alternative to the colonizer's allowance of self-determination,[citation needed] but in practice decolonization may involve either nonviolent revolution or national liberation wars by pro-independence groups. It may be intramural or involve the intervention of foreign powers acting individually or through international bodies such as the United Nations. Although examples of decolonization can be found as early as the writings of Thucydides, there have been several particularly active periods of decolonization in modern times. These are the breakup of the Spanish Empire in the 19th century; of the German, Austro-Hungarian, Ottoman, and Russian Empires following World War I; of the British, French, Dutch, Portuguese, Belgian and Italian colonial empires following World War II; of the Russian Empire successor union following the Cold War[citation needed]; and others.As a philosophy, "decolonization" refers to the ability to view and discuss non-European cultures from an unbiased, non-Western perspective.