2 The lust of lucre has done much to make the minds of men so barbarous. But something also is due to the nature of the climate and the situation of these regions. For, as these places are subjected to burning southern sun, which casts a languor into the veins and as it were, destroys the vigor of virtue, and as they are far removed from the habits of religion and the vigilance of the State, and in a measure even from civil society, it easily comes to pass that those who have not already come there with evil morals soon begin to be corrupted, and then, when all bonds of right and duty are broken, they fall away into all hateful vices. Nor in this do they take any pity on the weakness of sex or age, so that we are ashamed to mention the crimes and outrages they commit in seeking out and selling women and children, wherein it may be truly said that they have surpassed the worst examples of pagan iniquity.
Source: Lacrimabili Statu (Vatican.va)