Quaker Calendar

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This page is a long term project. I don't know how to make a calendar yet. So, while stumbling through as time permits, this page will be expanded. Eventually it may become useful!


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Please update or expand this section.

Gramps allows alternate calendars to be added to the date display and input parsing. This allows dates to be entered and displayed in the form found in the original records but then analyzed where dates are converted to a common calendar. Leaving the date in the date in the original form can help to prevent recursive conversion errors. The dominant calendar, used around the world since the reform of the Julian Calendar in the late 1500s, is the Gregorian calendar. But various cultures used other calendar systems. Gramps supports uses of those calendars as either the primary calendar or as an atypical notation on a specific Event date.

This page is an exercise in adding support for a new calendar type. The exercise begins with outlining the unique features of calendar and where it is applicable. Then the technical implementation continues with creating the calendar support files, installing them, then applying the calendar globally or exceptionally.

Computer internal calendars mean another conversion

Micro-computers tend to timestamp and datestamp based on an arbitrary starting day of the Gregorian Calendar.

The Unix epoch date (aka Epoch time, POSIX time, seconds since the Epoch or Epoch time) which counts the number of seconds since 00:00:00 UTC on 1 January 1970 but ignore leap seconds. It is a close approximation of Coordinated Universal Time (UTC) rather than a true representation.

The Windows API dating uses a millisecond-based SYSTEMTIME and 100-nanosecond ticks FILETIME since 00:00:00 UTC on 1 January 1601.

Outlining the Calendar

The calendar to be added is the Quaker calendar.

The religious Society of Friends (aka [Quakers]) are a Christian sect. (George Fox (1624-1691), a founder of the movement, wrote that the "Quaker" name was coined as a form of ridicule by the magistrate Gervase Bennet when Fox had been formally charged with blasphemy: "was the first that called us Quakers, because I bade them tremble at the word of the Lord".)

The Quakers found the Roman derived naming conventions on the calendar to be impious and offensive. (Many designations honored pagan gods and rites.) So they adopted a parallel calendar to the Julian and Gregorian reformed calendar which used different naming conventions. Like the Julian/Gregorian calendar, it is composed of the same divisions of 12 months and 7 day weeks. As with the European week, a Quaker week starts on the equivalent of Sunday. However, the weekdays and months are represented numerically rather than proper names. Until the Gregorian calendar reform, they did not object to the months names for September through December (seventh through tenth) as those were equivalent to being simple numeral prefixes. But after the Gregorian calendar reform, the numeral prefixes were off by 2 months and no longer made sense.

As with the introduction of the Gregorian Calendar, the reform cause great confusion. So a system of Dual Dating was used with a Proleptic New Style date overlaid on the Old Style to minimize the ambiguity.

Entering a Quaker date is probably easier using the Roman Numeral date parser. It eliminates the ambiguity in data entry. So '3 x 1776' and 'x 3 1776' will both parse to 'October 3rd, 1776'. But, roman numeral months in Old Style (Julian) are still parsed as New Style (Gregorian) month numbers... even when explicitly marked as 'Julian'. So even though the 10th month of the year in 1740 is before Great Britain and its colonies enacted the Calendar (New Style or Chesterfield's) Act 1750 (24 Geo. II c.23), an '3 x 1740 (julian)' will be re-written as '3 October 1740 (Julian)' instead of '3 December 1740 (Julian)'.

See also

RPG (role playing games) adaptability
unify similar surmanes [sic] thread
threads with "Group As name"