This specification defines 4 calendars: GREGORIAN, JULIAN, FRENCH_R, and HEBREW. Previous versions also provided for, but did not define the meaning of, ROMAN and UNKNOWN calendars.
Extension calendars should use the usual rules for extensions, including using _ as the leading character of the calendar name.
Each calendar must list its permitted epochs and their meaning.
All month tags must either be standard tags defined for the month name in some standard calendar or be extension tags.
Each month defined in this section has a URI constructed by concatenating g7:month- to the standard tag; for example, the month of Elul has the standard tag ELL and the URI http://gedcom.io/terms/v7/month-ELL.
Months with extension tags are permitted in standard calendars only when they are documented extension tags with standard URIs defined by the calendar. This is intended for future compatibility, to accommodate cases where an extension calendar later becomes standardized without changing the URI, at which point the calendar name and month names with _ are acceptable with the now-standard URIs.
GREGORIANThe Gregorian calendar is the now-ubiquitous calendar introduced by Pope Gregory XIII in 1582 to correct the Julian calendar which was slowly drifting relative to the seasons.
Permitted months are
stdTag | Name |
|---|---|
JAN | January |
FEB | February |
MAR | March |
APR | April |
MAY | May |
JUN | June |
JUL | July |
AUG | August |
SEP | September |
OCT | October |
NOV | November |
DEC | December |
The epoch marker BCE is permitted in this calendar; year y BCE indicates a year y years before year 1. Thus, there is no year 0; year 1 BCE was followed by year 1.
The URI for this calendar is g7:cal-GREGORIAN
JULIANThe Julian calendar was introduced by Julius Caesar in 45 BC and subsequently amended by Augustus in about 8 BC to correct an error in the application of its leap year rule during its first 3 decades. Years had been counted from various starting epochs during the Julian calendar’s use; the version specified by this specification uses the same starting epoch as the Gregorian calendar.
This calendar uses the same months as the Gregorian calendar, differing only in which years February has 29 days.
The epoch marker BCE is permitted in this calendar; year y BCE indicates a year y years before year 1. Thus, there is no year 0; year 1 BCE was followed by year 1.
The URI for this calendar is g7:cal-JULIAN
FRENCH_RThe French Republican calendar or French Revolutionary calendar are the names given to the new calendar adopted in 1794 by the French National Convention. This calendar was adopted on Gregorian day 22 September 1792, which was 1 Vendémiaire 1 in this calendar. It was abandoned 18 years later.
Permitted months are
stdTag | Name |
|---|---|
VEND | Vendémiaire |
BRUM | Brumaire |
FRIM | Frimaire |
NIVO | Nivôse |
PLUV | Pluviôse |
VENT | Ventôse |
GERM | Germinal |
FLOR | Floréal |
PRAI | Prairial |
MESS | Messidor |
THER | Thermidor |
FRUC | Fructidor |
COMP | Jour Complémentaires |
No epoch marker is permitted in this calendar.
The URI for this calendar is g7:cal-FRENCH_R
HEBREWThe Hebrew calendar is the name given to the calendar used by Jewish peoples around the world which developed into its current form in the early ninth century. It traditionally marks new days at sunset, not midnight. Its first day (1 Tishrei 1) primarily overlapped with Gregorian 7 September 3761 BCE and Julian 7 October 3761 BCE (starting at sunset on the 6th day of those months).
stdTag | Name |
|---|---|
TSH | Tishrei (תִּשְׁרֵי) |
CSH | Marcheshvan (מַרְחֶשְׁוָן) or Cheshvan (חֶשְׁוָן) |
KSL | Kislev (כִּסְלֵו) |
TVT | Tevet (טֵבֵת) |
SHV | Shevat (שְׁבָט) |
ADR | Adar I, Adar Rishon, First Adar, or Adar Aleph (אדר א׳) |
ADS | Adar (אֲדָר); or Adar II, Adar Sheni, Second Adar, or Adar Bet (אדר ב׳) |
NSN | Nisan (נִיסָן) |
IYR | Iyar (אִייָר) |
SVN | Sivan (סִיוָן) |
TMZ | Tammuz (תַּמּוּז) |
AAV | Av (אָב) |
ELL | Elul (אֱלוּל) |
To keep the lunar-based months synchronized with the solar-based years, some years have Adar I and others do not, instead proceeding from Shevat directly to Adar II. However, in common (non-leap) years, it is common to simply write “Adar” not “Adar II”, which users not aware of the distinction might incorrectly encode as ADR instead of ADS. It is recommended that systems knowing which years had Adar I and which did not replace ADR in common years with ADS.
No epoch marker is permitted in this calendar.
The URI for this calendar is g7:cal-HEBREW