Read the excerpt from "Benin Plaque: The Oba with Europeans.” Many wild theories were put forward. It was thought that the plaques must have come from ancient Egypt, or perhaps that the people of Benin were one of the lost tribes of Israel. Or the sculptures must have derived from European influence (after all, these were the contemporaries of Michelangelo, Donatello and Cellini). But research quickly established that the Benin plaques were entirely West African creations, made without European influence. The Europeans had to revisit, and to overhaul, their assumptions of easy cultural superiority. Which central idea is best supported by the details in the excerpt?