Factors that helped Europe colonize overseas territories are: military might; political strength and technological advances.
The first European colonization series occured from the early 15th century, and primarily included the European colonization of the Americas, though it also involved the establishment of European colonies in India and in Maritime Southeast Asia.
The time period in which much of the first wave of European colonization as well as other exploratory ventures took place is often refered to as the Age of Discovery.