The Maths-Classics project

Assignment 6

The Roman calendar

The months and the year

Many peoples, among them the ancestors of the Romans, observed that the moon goes through a complete cycle from new to full and back again every 28 days. This they called a month (mensis - connected with the word moon). They also observed that the seasons - spring, summer, autumn and winter follow a regular pattern. The problem begins when you try to match up months and the year - because of variations in weather etc, it isn't easy (without complex astronomical data) to discover exactly how many days from one spring to the next. So the Romans' ancestors assumed it must be 10 months. [How many days?]

What difficulties would soon become apparent? How would you solve them?

The Romans therefore took to adding two extra months each year (known as intercalary months) - how many days now?

Is there still a problem? How did the Romans solve it?

One of the problems that remained was that the months could be inserted at any time, at the discretion of the priests! And adding a few days to each month more or less solved the problem.

But we all know now that there isn't an exact number of days in a year - there's an extra 25% or so of a day each year - and these will gradually mount up and cause problems again.

Julius CaesarSo in 46 BC Julius Caesar (who, through his astronomers had access to the scientific data) ordered a reform of the Calendar. The number of days in each month was fixed ("30 days hath September ...") - and the two extra months of January and February were added at the beginning of each year [What month had the Roman year originally started in?]. To cope with the extra quarter of a day, he added an extra day to February every four years. And we are still using his calendar nearly 2000 years later! (With a few minor tweaks added by Pope Gregory XIII in 1582) .

So you won't be surprised to know that the names of our months are all Roman:

mensis ianuaria - the month of Janus (two-faced god of entrances and exits)

mensis februaria - the month of fevers

mensis martia - named after which god?

mensis aprilis - the month the Earth opens and softens (from Latin aperio, I open)

mensis maia - named for the goddess Maia [whose mother was she?]

mensis iunia - named for another goddess [which?]

mensis quintilis - the fifth month [why? Why was it renamed mensis iulia?]

mensis sextilis - the sixth month. How was it renamed, and in whose honour?

mensis septembris - the seventh month (obvious why by now?)

mensis octobris - [meaning?]

mensis ............

mensis ............

The days of the month

[note the Romans did not have the concept of week - where did that come from? Follow this link to discover the strange and sexy origin of the week we all know - http://www.classicspage.com/week.htm]

This is quite complicated! Each month had three fixed points: