...The Zapotecs may have devised the earliest 260-day divinatory calendar. Following Caso’s pioneering work, Javier Urcid later spent ten years drawing and recording hundreds of Zapotec glyphs, and comparing the day and year signs to words in the Zapotec language. Through a tedious process of comparison and elimination he reconstructed an entire day sign list as well as the four year bearers...[1]
