Naturalist's Almanac

Why does February have only 28 days? You’d think with seven 31-day months, it would have been easy enough to give February 30, but calendars have never been easy. When the Romans first began working on the one that has become ours, February didn’t even exist.

The problem from the beginning was to reconcile the moon’s 29 1/2 day month with the sun’s 365 1/4 day year. The Romans’ first effort, supposedly devised by their founder, Romulus, included 10 months that added up to only 304 days. Clearly, Romulus had not conceptualized the problem.

The legend continues that King Numa Pompilius added January and February. The days now added up to 355, approximately the number in 12 lunar cycles but still 10 to 11 days short of a solar year. So Numa invented an extra month called Mercedinus that would be added to February every other year.

Numa’s calendar was getting closer to a system that would work, but its lingering attachment to the lunar cycle made it unwieldy. Julius Caesar decided to ignore the lunar cycle and get rid of Mercedinus by arranging the number of days in the twelve months to add up to exactly 365 1/4. February wound up with 29 days plus an extra every fourth year.

Julius Caesar’s calendar, which is referred to as the Julian calendar, is essentially the one we use today — with a few minor adjustments. It may have been Augustus, or maybe his admirers, who made the final adjustment to February. February 29 got shifted to August, which had been named in honor of Augustus, because August needed an extra day to be equal to July, which had been named in honor of Julius.

So that’s how February came to be only 28 days. Interestingly enough a recent proposal for calendar reform suggests that all months should have 28 days and that there should be 13 of them. This fixed calendar would add up to 364, requiring only one extra day— two in leap years — to make the calendar dead simple.

If math were all that mattered it might work, but our current calendar’s luni-solar roots are deeply embedded in our religious, cultural, and even business lives. The irregular civil calendar that governs our days remains our most enduring connection to these ancient roots.

MORE INFORMATION

Early Roman Calendar
http://webexhibits.org/calendars/calendar-roman.html

Lots of interesting information arranged in an question-and-answer format with some interesting reproductions of old Roman calendars.

Roman Calendar
http://www.highdown.reading.sch.uk/highdown/pupil/time/calendars/earlyrom.html

Bill Hollon, the author of this Web site, has put together a lot of information on calendars and calendar history. For a glimpse of what’s available, visit his Site Map. His discussion of the Roman calendar includes an explanation of February, its addition to the calendar, and Mercedinus. If what he says sounds familiar, it’s because he gave the Web Exhibits site permission to borrow much of his text. For Hollon’s explanation of why February has only 28 days, visit the next link.

Octavian's Changes
http://www.highdown.reading.sch.uk/highdown/pupil/time/calendars/octavian.html

Hollon offers a substantial discussion of Octavian (the emperor we call Augustus) and his adjustments to Julius Caesar’s calendar.

Romans' Messy Calendar
http://www.tondering.dk/claus/cal/node3.html#SECTION00380000000000000000

That's 16 zeros! This link will take you directly to the section of Claus Tondering's FAQ's that discusses the Roman calendar. Tondering questions how much we really know about early Roman calendars and Augustus' adjustments to the Julian calendar. Tondering also made major contributions to the Web Exhibits' information on the Early Roman Calendar.

Calendar Reform
http://personal.ecu.edu/mccartyr/calendar-reform.html

This Web site offers lots of background information on calendar reform. Scroll down to the bottom of the introductory text, and look for links to the various 13-month calendars that have been proposed. This site takes no sides. It is devoted to history rather than advocacy.