The history of the conquest of America has constituted a primary source of self-perception and identity formation for Western nations, feeding their imagined superiority over the other nations of the world. This comparative study shows that modern Western historical knowledge is linked much more closely to Arab knowledge than it is to a pure Greco-Roman origin, contrary to the commonly accepted idea in contemporary Western thought. It compares the work of Spanish historians on the conquest of America in the sixteenth century CE with Arab texts concerning the conquest of Andalusia written in the 9th and 10th centuries AH, drawing out similarities between the two stories. It concludes that the narrative of the conquest of America is a copy of the Andalusia conquest narrative, reclaimed by the Spanish at the beginning of the modern era. It thus affirms the diverse origins of western knowledge against the claim that it is purely Greco-Roman.