Colonialism is the establishment, maintenance, acquisition and expansion of colonies in one territory by people from another territory. It is a process whereby the metropole claims sovereignty over the colony, and the social structure, government, and economics of the colony are changed by colonizers from the metropole. Colonialism is a set of unequal relationships between the metropole and the colony and between the colonists and the indigenous population. Colonialism and imperialism are ideologically linked with mercantilism.