Inhabitants of the New World may have started writing things down much sooner than scientists thought. According to a report published today in the journal Science, nearly-2,700-year-old engraved plaques and a cylindrical seal from Mexico indicate that Mesoamerican people developed a system of written communication 350 years earlier than previously believed.

Mary E. D. Pohl of Florida State University and her colleagues recovered the relics from a pile of debris left by the Olmec people after an ancient festival at San Andrs, located in the Mexican state of Tabasco. By carbon dating charcoal located above and below the finds and analyzing layers of ceramics at the site, the researchers determined that the artifacts date to 650 years B.C.. Researchers had already discovered related hieroglyphic scripts and a 260-day calendar from the people of the Mayan, Isthmian and Oaxacan regions in the so-called Late Formative period hundreds of years later. "This find indicates that the Olmecs' form of written communication led into what became forms of writing for several other cultures," says John Yellen of the National Science Foundation, which supported the research.

The fist-sized seal (see image) depicts two so-called speech scrolls emerging from a bird's mouth. The scientists note that one of the markings on the seal closely resembles the Mayan word for king, ajaw. Another graphic contains the word "3 ajaw," which refers to a date on the calendar. Because common practice at the time involved christening people with the date of their birth, the authors suggest that the seal was used to print a royal message on a variety of surfaces, including paper, cloth and skin.