Solar Calendar -- When was the leap day inserted?

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Discussion Overview

The discussion revolves around the historical insertion of leap days in solar calendars, particularly focusing on the implications of different starting points for the year, such as March 1. Participants explore when leap days were added in relation to various calendar systems, including the Julian and Gregorian calendars.

Discussion Character

  • Exploratory
  • Debate/contested
  • Historical

Main Points Raised

  • One participant questions when leap days were inserted if the year started on March 1, suggesting that it might differ from the January-based system.
  • Another participant asserts that leap days can be inserted at any time, as long as the general rule of one every four years is followed, indicating flexibility in the calendar system.
  • A participant seeks clarification on whether the leap year would be considered the year before (e.g., 1665) if the year starts in March.
  • One response indicates that the leap day was inserted one year late during the period of calendar use, although the reasoning behind this is not fully elaborated.
  • A later post references a source suggesting that in a calendar starting on March 1, the year 1439 would be a leap year, as it aligns with the leap year in the January-based reckoning.
  • Another participant notes that the determination of leap years may depend on decisions made by the Church regarding the calendar used at the time.

Areas of Agreement / Disagreement

Participants express differing views on the specifics of when leap days were inserted in relation to the calendar start date, indicating that multiple competing interpretations exist without a clear consensus.

Contextual Notes

There are unresolved assumptions regarding the historical practices of intercalation and the specific calendar systems in use during different periods, which may affect the understanding of leap day insertion.

ethan2
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solar calendar
If the year started on, for example, 1 March(in some places during the 15th century), two months later than our present year, when was the leap day inserted?
Thank you.
 
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Whenever you want. You just need one every four years (plus minor adjustments) - there's no need for it to be any particular date.
 
thanks.
however my question was when really it happenned? Meaning, if the year starts the first january the leap year is on the year you can divide by 4(let's say 1666).But when the year started in march was the leap year the year before(1665)?
 
I see. No idea - probably searchable, though.
 
Ibix said:
I see. No idea - probably searchable, though.
no problem thanks
 
Baluncore said:
thank you very much
i did however found this on the web (though he is not sure) :"

Then what about leap years?​

If the year started on, for example, 1 March, two months later than our present year, when was the leap day inserted?

When it comes to determining if a year is a leap year, since AD 8 the Julian calendar has always had 48 months between two leap days. So, in a country using a year starting on 1 March, 1439 would have been a leap year, because their February 1439 would correspond to February 1440 in the January-based reckoning.
 
ethan2 said:
If the year started on, for example, 1 March, two months later than our present year, when was the leap day inserted?
It depends on what the Church decided it should be, with the calendar they used back then.

"Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases." Wikipedia.
 

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