the same issue of Natural History (April) that has the article about dying languages (visigoth thread) has as its lead article (not available on line)on the Codex Borgia, an Aztec document, represents half of a 260-day ritual calendar.
http://www.amnh.org/naturalhistory/index.html
It seems the aztec calendar had unique days-- I fox, 2 wolf, 3 deer-- which repeated once every 52 years! so in effect your the day of your birth also named the year of your birth! All of this was even more confussing since the Aztecs also had a 365 solar calendar-- (as well as the 260 ritual calendar!) -- and i have trouble enough remembering what day of the week it is!


my other obsession