Roman Dates

[MonsGraupius]

Did the calendar year start on March 25th in this period?

I believe that the new year was moved to Jan 1st during the late republic, to fit with the start of the consular year, which began on this date. Why the situation seems to have been changed back again in more recent times (which is why we have the old style/new style thing) I don't know!

The year start was probably 1 May before 222 BC, 15 March from 222 BC and 1 January from 153 BC.

What I can't get my head around is what the day/month would be if we projected our modern calendar backwards to the Roman period.

I know there were 11 days lost in September 1752. But looking at the following, it suggests this was less than a day out from 46BC to 82AD

Before 1752, Britain and her Empire followed the Julian calendar, first implemented by Julius Caesar in 45 BC However this calendar had an inbuilt error due to a miscalculation of the solar year. This affected the date of Easter, traditionally observed on March 21, as it began to move further away from the spring equinox with each passing year.

To get over this problem, the Gregorian calendar was introduced. This is offset by a number of days from the Julian Calendar (which varies with year. But otherwise the months have the same length as the Julian Calendar except February, which still consists of 28 or 29 days except leap years occur in a slightly different pattern.

First to adopt the new calendar in 1582 were France, Italy, Poland, Portugal and Spain. Turkey was the last country to officially switch to the new system on January 1st, 1927. The Calendar (New Style) Act 1750 introduced the Gregorian calendar to the British Empire, bringing Britain into line with most of Western Europe.

In 1563 the correction restored the date of the vernal equinox to that held at the time of the First Council of Nicaea in 325.

However, I read the difference between the Julian and Gregorian Calendars = [Y/100] - [Y/400]  -2  ([] - means round down to the nearest integer, Also for BC years use "year_BC − 1"). Note: Julian Calendar took effect 1 January 45 BC (AUC 709)

In the following years our modern Gregorian Calendar would not have a leap year (I.e. 29th Feb) whereas the older Julian Calendar had 29th Feb. So the calendar has a set offset until the 28th Feb JULIAN. Then we skip a day.


So the number of days our present Calendar is ahead of the Julian Calendar is:-

From present calendar to Julian
1st Jan   45BC to 26th Feb 100AD =  +2 days (27th Feb 100AD = 29th Feb Julian, 28th Feb = Julian 1st March. 1st Mar = 2nd Mar))
1st Mar 100AD to 27th Feb 200AD =  +1 days (28th Feb 200AD = Julian 29th Feb; 1st Mar = 1st Mar)
1st Mar 200AD to  28th Feb 300AD =  0  days (1st Mar 300 = Julian 29th Feb)
2nd Mar 300AD to 1st Mar 500AD = -1 days (2nd Mar 500 = Julian 29th Feb)
3rd Mar 500AD to 2nd Mar 600AD = -2 days (3rd Mar 600 = Julian 29th Feb)
4th Mar 600AD to 3rd Mar 700AD = -3 days (4th Mar 700 = Julian 29th Feb)
5st Mar 700AD to 4th Mar 900AD = -4 days (5th Mar 900 = Julian 29th Feb)
6st Mar 900AD to 5th Mar 1000AD = -5days(6th Mar 1000 = Julian 29th Feb)

But just a warning, I remember reading somewhere that the pattern of leap years is uncertain until around 1AD. So, whilst people will produce rules about the date BC, the truth is we really do not know. So read "BC" as "Before Calendar" - in the sense that exact day dates are uncertain.