Effigy Mask of Coyolxauhqui (“She Who Has Facial Painting with Bells”), ca. A.D. 1500. Mexica culture, Mexico, Tenochtitlan. Greenstone. H. 4 1/8 × W. 5 11/16 × D. 1 9/16 in. (10.5 × 14.5 × 4 cm). Peabody Museum of Archaeology and Ethnology, Harvard University, Anonymous Gift, 1928 (28-40-20/C10108) © Peabody Museum of Archaeology and Ethnology, Harvard University

This greenstone effigy mask represents the severed head of Coyolxauhqui. According to myth, her brother Huitzilopochtli, the Sun God and patron deity of the Mexica, was born fully armed and slayed his four hundred siblings. This battle signified the cosmological struggle between the moon and the sun, and it also had political overtones, as Coyolxauhqui represented the vanquished enemy and served as a warning to those who challenged the Aztecs.