For Southern slave owners who were faced with the abolitionist movement to end slavery, the curse of Ham was one of the only grounds upon which Christian planters could formulate an ideological defense of slavery. Even before slavery, in order to promote economic motivations within Europe associated with colonialism, the curse of Ham was used to shift the common Aristotelian belief that phenotypic differentiation among humans was a result of climatic difference, to a racialist perspective that phenotypic differentiation among the species was due to there being different racial types. This often came as a result of European anxieties to avoid being sent to the colonies, as they were terrified of the high casualty rate of settlers due to disease and warfare. Thus, many of them formulated the idea that being sent south of the equator "blackened" them and thus made them inferior.