While historians usually divide episodes of European colonialism or imperialism into separate eras, there are nonetheless consistencies in motive between those eras. The first commonality is the desire for natural resources. The second motive is the creation of controlled markets in the colonies, and the third reason is military and geopolitical strategy.
By the early modern era, much of Europe was overcrowded, leading to a shortage of food, space and other resources. However colonies offered potential riches in crops and materials as diverse as cotton, sugar, tobacco, iron ore, flax and fish. By controlling these newly discovered areas, Europeans could also control the harvesting and use of these materials. Furthermore, by allowing colonists to harvest these materials but not create their own finished goods, the European powers ensured that their own factories would supply them instead while people back in the colonies would be forced to buy them at a fixed price. Thus, the addition of colonies completed an economic circuit in which the colonial power could control resource extraction, commodity production and commodity distribution without any form of external competition. Finally, European powers often used colonies to protect other colonial interests. For example, British colonial operations in the Suez and South Africa were not only localized concerns but a means of safeguarding vital routes to the most important British Imperial possession of the modern era, India. During the infamous "Scramble for Africa" of the 19th century, European powers literally raced to procure colonies on that continent as fast as possible, often simply grabbing land before other competing colonial nations could.