Colonial Ideology 

A colonial ideology is the internalised belief of ethnic or cultural superiority resulting in a need to dominate and change a group seen as inferior. From the perspective of the coloniser, this might mean believing that their culture is superior and so that they need to change the culture's of others. From the perspective of the colonised, they might then feel inferior and needing to fit an idea of culture presented from the coloniser. 

Colonisation, historically, was done in service of THE THREE Cs: giving Christianity, commerce, and civilization to nations seen as 'savage' and, therefore, needing it.