December hasn’t always been the 12th month in the calendar. “December” comes from the Latin word “decem,” meaning “10,” and was originally the 10th and final month in the Roman calendar.

December’s place changed, however, when Julius Caesar decided to reform the Roman calendar, which was so irregular that the celebration of festivals occurred during the wrong seasons of the year.

So after consulting the Egyptian astronomer Sosigenes, Caesar established his new 365 day Julian calendar in 45 B.C.E., which was longer than the Roman calendar and increased the number of days in December from 29 to 31.

In 2011, December’s 31 days mean the inevitability of snow and the imminent transition to a new year. Usually, the last of those 31 days also carries with it the idea of an end.

Despite the addition of days and debates on how to properly measure time, December, as an end, is primarily symbolic: A new calendar is tacked on the wall in place of the old one, and the countdown begins again.