A number of factors played into European imperialism during the 19th Century. These included economic, political, military, religious, and sociological motives.
The rising European economies of the Industrial Revolution meant that the demand for resources, cheap labor, and trade routes was at a premium. By acquiring colonies, European powers could exploit the resources of these colonial holdings and use the local population as laborers. Some colonies were acquired for the purpose of securing important shipping lanes and trade routes. This was the case with Great Britain and the Suez Canal in Egypt and with the Dutch and the Straits of Malacca. By controlling the source of raw materials, labor, and transportation, European powers effectively used their colonial holdings to grow their economies.
Political competition between the European powers was also a major motivator to expand colonial holdings. By the latter half of the 19th century, a land grab was in effect, particularly in Africa and Southeast Asia. Colonies had to be secured—and secured quickly, before one's rival could snatch them up.
As European powers were expanding their military might abroad, they needed to secure strategic bases around the world. In the age of the steamship navy, coaling stations were of extreme importance. As a result, many colonial holdings were established as military outposts.
To a certain extent, religious motivations also played into European imperialism. Christian missionaries established churches and schools around the world. Sometimes these missionaries were the vanguards of imperialism. For example, French missionaries in Vietnam were some of the first to encourage their nation to colonize Indochina.
Feelings of cultural superiority also contributed to European imperialism. These sociological motives were often used to justify the subjugation of local populations. Many European peoples felt that their customs and values were superior to those of other peoples. It was "the white man's burden," as Rudyard Kipling put it, to "civilize" these peoples.