Colonialism, the search for overseas markets and raw materials led to the establishment of colonies: namely, the colonial country (e.g. Britain, France) would set up a government in the colony (e.g. India or Indochina), with the top levels of a bureaucracy usually staffed by appointees from the colonial country.  One could trace the beginning of modern colonization to the 16th and 17th centuries. 

Imperialism: after the Industrial Revolution, colonialism more and more became an integral part of a European government's agenda and a routine policy.  More resources were put into the acquisition of colonies, protectorates, and spheres of influence for wealth, power and prestige of the mother country. (McClain, 291)

Governments often used such conquests to display their muscle, especially when such a display was lacking at home.  France's expansion, for instance, helped French citizens feel compensated for losses suffered in the Franco-Prussian War.  Italian conquests overseas promised to make up for Italy's failure to acquire first-rate power status on the Continent.  To be left behind in the imperial race marked a nation as second class.

Imperialism was also often the flipside of nationalism.  The 19th century European definition of the nation emphasized the similarity of race or ethnicity, shared culture, history, religion, and customs.  Combined with Social Darwinism, people of other countries were often labeled of an inferior race, therefore justifying their colonization, so that they would be "civilized."