The Aztec believed that every natural and human activity was subject to an order imposed by the universe. Because Aztec rulers were thought to be semidivine, much of the art associated with them was infused with cosmic symbolism to add further legitimacy to their claim to imperial power. The central panel of this altar is carved to represent the fifth, and last, sun in the Aztec creation myths, which signified the era of Aztec rule; the same image appears on the famous Aztec calendar stone in the National Museum of Anthropology in Mexico City. This motif is surrounded by the sun's disk, and on the sides are a series of dots representing stars. Other reliefs show flint knives and skull forms, which symbolize sacrifice and the earth. During the ceremonies in which Aztec rulers were confirmed, blood offerings to the earth and sky were made at this altar. It was originally associated with a major but as yet identified temple in Tenochtitlan, the capital of the Aztec empire, a site now occupied by central Mexico City. Allen Wardwell, from Philadelphia Museum of Art: Handbook of the Collections (1995), p. 56.