Key Stage 3: Mathematics

Number systems and dates in medieval England.

Our modern numbering system 1,2,3 etc is derived from Islamic mathematicians.

For formal documents in medieval England, several different ways of numbering were used.

The Roman system of letters, as shorthand for numerals, has been in use in England since the Roman invasion of AD 43 and is still used by publishers e.g., MMXXII, Kings & Queens e.g., Elizabeth II, Popes e.g., Benedict XVI and on some clocks and watches.

The basic Roman numerals can be seen here. There was no Roman symbol for zero – we owe that to Muslim scholars.

Dates were represented in at least three different ways.

Old Style Julian Calendar (devised by Julius Caesar) with months and days as now.

In 15th century England the first day of the calendar year was 1st January as it is for us, but the number they gave to each year didn’t change until March 25th (Lady Day). This is because the numbers signify the years since the Incarnation (God becoming man as Jesus) and March 25th was celebrated as the day of Jesus’s conception. This means that January, February and most of March were counted in what we would call the previous year. The number of the year only started changing on January 1st in the middle of the 18th century.

A Regnal year began on the day someone became king, with 1 and the name of the reigning monarch. Richard’s regnal year began on 26 June 1483 as 1 Richard III and this is how Parliament dated new laws.

A Liturgical (Church) calendar marked the feast days of Saints e.g. the Feast of St John the Baptist is always June 24th just as Christmas now is always December 25th.  Easter is a moveable feast.

Because the Catholic Church was so much as part of life in the fifteenth century, everyone would be tuned into the liturgical calendar as well as to the regnal years so both systems were reliable for arranging events within twelve months (a ‘twelvemonth’ rather than a ‘year’ because the latter could have several meanings.)

Labours of the month: October © Trinity College Cambridge Library

Your Task

Make a calendar for one month during King Richard III’s reign. You can choose any date between 26 June 1483 and 22 August 1485 in the Old-Style Julian calendar.

Use Roman numerals for the days of the month.

Look up the main feast days for your month here and include these by name.

Add in what we know of Richard’s whereabouts on each day, to create a medieval court diary.

Add some illustrations to make your calendar look more like a medieval one.