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.

So 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:

• Kalendae (the Kalends) - the first day of the month.
• Nonae (the Nones) - on the 5th or 7th day of a month (although the word seems to mean 9th!)

  "In March July October May
  The Nones come on the seventh day"

• Idus (the Ides) - on the 13th or 15th of each month

  "In March July October May
  The Ides fall on the fifteenth day"

  [So what date was the Ides of March, and why are the Ides of March 44 BC famous?]

  So the first of the month of January was kalendae ianuariae (or kal.ian. for short). Abbreviations were always used - and no capital letters.

  The second of January was four days before the Nones ( N.B. the Romans counted on their fingers, using the day they were on and the day they were counting to) - so they called it (for short) a.d.iiii non.ian (four days before the Nones of January - a.d iiii here stands for ante diem quartum, "the 4th day before")

  The third of the month was three days before the Nones, so they called it a.d.iii non.ian.

  The fourth of the month was two days before, logically, but they always called it pridie (the day before) - prid.non.ian

  The fifth - easy - non.ian (the Januarian Nones) - but what about the 6th?

  The sixth - count up to the Ides on the 13th (using fingers!) - thus : a.d.viii id.ian. You can now work out the dates up to the Ides:

  7th a.d. .... id.ian

  8th ....................     9th ....................    10th.....................    11th....................    12th (careful!)....................     13th ....................

  So how would you say 14th January? It should now be obvious: the next fixed point is the 1st February (Februarian kalends), which is 19 days away by Roman reckoning, thus a.d.xviiii kal.feb (or a.d.xix kal.feb if you must). Complete the rest of the calendar for January.

  The rest of the year will thus be plain sailing - but do you remember which months have their Nones and Ides on the 7th and 15th days? Note the months are usually abbreviated to their first three letters (except March which is mart., July which is quint., August which is sext. and September which is sept.)

  Work out : today's date .............................................

  your birthday ....................................................

  your teacher's birthday ................................................. (get them a card at least!)

  What dates are these? a.d. viii kal. ian ...................................

  a.d.iii id.mai. (my birthday!)

  non.nov. ......................................     prid.kal.nov ..................................       a.d. x kal. mai. (whose birthday?) ..................................

  prid.id.sext (or aug) ................................        a.d. iiii non.quinct. .............................