Era names and codes for ethiopic

[Louis-Aime]

As said, ethiopaa calendar has only one era, so no era code is necessary.
Generally, this unique era is called "Anno Mundi", but you can also call it "Amete Alem", abbreviated "A. A.", narrow "A".

Here is one possible source : https://www.google.fr/books/edition/Internal_Rivalries_and_Foreign_Threats/hCqedAA_Z5IC?hl=fr&gbpv=1&dq=amete+alem&pg=PR11&printsec=frontcover

ethiopic use two eras. Expert name the current one "Age of Mercy" ("An de grâce"), or "Incarnation", but IMHO, if we display the months as a transliteration of the original language, we should do the same for the era. If you follow the beforementioned source, you can use:

• Amete Alem -> code aa
• Amete Mihret -> code am

These codes are simple, unique, and well understood by people who know about the Ethiopic culture.

BTW, the first era displayed by Intl. should be "Amete Alem" or "Anno Mundi" or "from the World's Creation" but NOT "before Incarnation", as years are not counted backwards, but from the year -5493 epoch.

[sffc]

If we adopt the proposed Gregorian era codes in #5 (comment), then we should most likely follow the same convention of using the calendar ID as the era code name here for Ethiopic, too.

This would mean era codes should be

• ethiopic = Amete Mihret / Incarnation (current era)
• ethioaa = Amete Alem / Anno Mundi

It's unclear from what I can find online whether dates before Amete Mihret are rendered counting backwards (B.C. style), or whether they count forwards from the Amete Alem epoch. I've found https://ethiopiancalendar.wordpress.com/history/ to be a fairly informative source, though it's hard to verify. It does say the following:

The Geez Calendar (ቀለንጦስ) is divided into old and new. The old era which is equivalent to the B.C. is Zemene Bluy (Z.B.) or (ዘመነ ብሉይ). Zemene Haddis (Z.H.) or (ዘመነ ሓዲስ) is Anno Domini (A.D.), though it is commonly referred to as Amete Mihret (A.M.) which means “years of mercy”.

To support the case of Zemene Bluy:

• pre-ethiopic = counting backwards from Amete Mihret (year 1 in pre-ethiopic is the year before year 1 in ethiopic)

The good thing is that we don't really need to know which one is the canonical representation. We can support pre-ethiopic for input, and if we later find that it is invalid for output, we can just stop outputting it, but we can still accept it as input.

Another case here is how we write dates that are before the beginning of Amete Alem. According to the Ethiopian church, such dates simply don't exist. However, since they exist in ISO-8601, we should have a way of representing them. I think in this case, as in other cases, we just use negative numbers in the ethioaa era.

[Louis-Aime]

@sffc has found a treasure about calendars in general, not only about the calendars of Ethiopia.
Let me quote a part:

According to Ethiopian scholars such as Aleqa Kidane Wold Kiflie (ኣለቃ ኪዳነ ወልድ ክፍሌ), the Ethiopic Calendar A.D. differs from other Christian calendars because of the continuity to these years after completion of the 5500 years and the former is religious while the latter is based on history. The Ethiopic years are seven years behind the Western and Eastern Church calendars. The seven years difference by Meskerem 1 or መስከረም ፩ becomes eight on January 1. Ethiopic uses the 5500 E.B.C. years in proleptic as well as modern calendrical calculations.

This says that the Ethiopic calendar is used "in proleptic" for years before incarnation, i.e. that calendar is used for a period of time where it did not exist. But the author also mentions "the continuity to these years after completion of the 5500 years" as a difference with other Christian calendars.

One does not see why defining an epoch, here 5500 years before 8 A.D., other than for a starting point. Scaliger had the same idea when he defined the "Julian Day 0" as Jan. 1, 4713 B.C.: taking a day very far in the past, he had the intention to count only forwards.