(from the archives of C. Julius Caesar)

Health and prosperity to you, great Julius Caesar.

I have studied the calendar of the Roman People that you sent me with much interest, and I thank you for the many illuminating comments you have made in the margins.

High Priest and Astronomer, know that the evident defects of the arrangements you detail, can be corrected.

Your people have long used, as you say, the waxing and waning of the moon as their principal measure of the calendar, with the Ides or full moon marking the centre of each month.

As the moon’s phases do not correspond to the length of the solar year, and it is the sun which makes the crops grow, this leaves your calendar year some ten and one quarter days short of the farmers’ year. And so the actual beginning of your farming season is occurring at quite the wrong season as marked by the calendar.

I have understood that your College of Priests have the power to declare an extra month called Intercalans or Mercedonius at intervals to correct this. In Egypt too we have a strange month of four or five days which is declared annually to correct the counting. We seem both to be agreed that, custom aside, this is a cranky resort.

In Rome to declare such a month is a political gesture as it preserves politicians in office for many extra days, and so is often not done. In Egypt we are ruled by Divinity and these questions do not arise. Our calendar remains accurate.

Great Caesar, make your year to be one of three hundred and sixty five days, and decree that one extra day is to be added every fourth year.

The unevenness of the months matters not and is not worth reforming, because the moon is rightly no longer the measure of the year.

With the minimum adjustment you may measure your year truly and still set the term of office for magistrates exactly.

As for the many extra days that must be added to the first year, there will indeed be confusion and much foolish popular discontent. Men do not like to see the order of things change, even when the result will be order in place of disorder.

This calendar will be more accurate than that used even in Egypt, and will preserve your name for ever as men learn to mark their time by it.

I am sending with this letter a full prospectus for the scheme, and await your observations with interest.

Your servant

Sosigenes, Chief Astronomer to The Divinity Cleopatra of Egypt.