The oldest evidence of the Maya calendar has been excavated at San Bartolo, Guatemala, found among fragments of painted murals. According to a new study, two fragments with a "7 deer" date notation date to between 300 and 200 BCE, based on radiocarbon dating. Authors of the study said that the finding "represents a day in the 260-day divinatory calendar used throughout Mesoamerica and among indigenous Maya communities today." "It's ...