This question can be directed at two different time periods so both will be addressed here. The European powers were involved in two distinct ages of colonialism: one during the 15th and 16th centuries as they colonized the New World in the Americas and the other during the 18th and 19th centuries as they essentially divvied up the entire continent of Africa amongst the strongest European nations. In both cases, they justified their cause with a catchy, three part phrase.
For the early colonists setting sail for the New World, they took off with the mantra of “glory, God, and gold.” To them, this also would eventually come to sum up their perceived superiority over the native populations. For glory, arguments were made that because these people could not defend themselves against modern European weapons in glorious battle that they did not deserve to be free. For God, it was argued that because they did not believe in the same God that the Europeans did, they were religiously inferior. And for gold, because the natives did not value gold more than baubles or trinkets, they were simple minded and knew nothing of economic value. These three factors not only made a great team chant, but gave concrete excuses for the Europeans to justify their actions.
Two centuries later, the argument is not much different when they enter Africa chanting “Christianity, commerce, and civilization.” This time, rather than reasons as to why the Europeans are superior to the natives, this three part saying describes the things that Europeans will bring the natives to improve their lives. Christianity to save their souls, commerce to make them rich and give them a system of economics, and civilization to turn them from the inhuman savages that they once were into proper enlightened human beings. For an excellent example of this, check out the children’s book series and cartoon “Babar.”