Recently Stuart has developed new research in the iconography and script of central Mexico, especially among the Mexica. In 2018 he presented a new and controversial interpretation of the so-called Calendar Stone of Tenochtitlan, suggesting it is not an image of an Aztec deity, but rather a deified portrait of the emperor Moctezuma II as the sun. Stuart emphasizes its role as a political monument and image, the purpose of which was to depict the Tenochca ruler at the center of the cosmos.