New Imperialism refers to the colonial expansion aopted by Europe's powers and, later, Japan and the United States, during the 19th and early 20th centuries; approximately from the Franco-Prussian War to World War I (c. 1871–1914). The period is distinguished by an unprecedented pursuit of what has been termed "empire for empire's sake," aggressive competition for overseas territorial acquisitions and the emergence in colonizing countries of doctrines of racial superiority which denied the fitness of subjugated peoples for self-government.