One of the best-known theories focuses on economic profit as the chief reason for a nation to seek foreign territories. Industrialized nations can produce more manufactured goods than their people need or can afford to buy. Colonies may serve as markets for these unsold products. They also may provide cheap land, valuable natural resources, and investment opportunities for surplus capital. However, this theory does not fully explain imperialism because many colonies were not economically profitable.
Military strategy is another important motive for imperialistic activity.
Since ancient times, nations have absorbed territory near their borders to protect themselves from foreign attack. Such territory serves as a buffer zone. In the late 1800's, many European powers had colonies throughout the world where their ships, both naval and merchant, could take on supplies. Imperialism can also be encouraged by patriotism, religion, and a sense of cultural and racial superiority. During the late 1800's, a strong feeling of nationalism swept most European countries.