Description First drawing in the book 'Descripcin histrica y cronolgica de las dos piedras que con ocasin del nuevo empedrado que se est formando en la plaza principal de Mxico, se hallaron en ella el ao de 1790'(or 'Historical and chronological description of the two stones found during the new paving of the Mexico's main plaza.' in English ) by Antonio de Leon y Gama (1792). The book describes Aztec calendars and specifically the discovery of the Aztec calendar stone in Mxico. The image depicts an aztec sun calendar.