 Contempt for biological hybridity did not end with the fall the Roman Empire, but continued throughout the Middle Ages and well into modern times, reaching a peak in the nineteenth century with the rise of Europe into an unrivalled imperial power.Hybridity and fear of racial degeneration caused by the mixing of Europeans and non-Europeans were major concerns in 19th century colonialist discourse prompted by racist pseudo-scientific discourses found in such works as Joseph Arthur de Gobineau's "Essai sur l’inégalité des races" and Joseph-Ernest Renan's "L’Education culturelle et morale".As an explicative term, hybridity became a useful tool in forming a fearful discourse of racial mixing that arose toward the end of the 18th century.