Actually, it's all connected to the study of calendars, the one we call the ferenj calendar is called Gregorian Calendar, named after Pope Gregory. What Gregory did in the 15th century was change the calendar they used because the previous calendar (called Julius Calendar) had leap year problems meaning every few centuries hours and days when an accounted for. To simplify things, ever since Julius Caesar introduced the Julius calendar to the roman empire around the 50 BC, the calendar has not been counting this leap days we find in the present calendar when February is 28 and some months are 31, this is not true in the Ethiopian calendar because we have added this leap days to one month with 5 to 6 day and called it "puagme". So the Julius Calendar just didn't count this leap day at all and by the time of Pope Gregory 10 whole days were an accounted for in the calendar and the calendar was becoming useless in keeping seasons and lunar seasons. So Gregory changed the calendar with one that counts the leap days in a year and the leap seconds in the days. And that calendar became what we now know as the ferenj calandar. #HistoricalFact the day Gregory changed the Julius Calendar (J.C.) to Gregory Calendar (G.C.), 10 days went missing on the calendar. The people went on a riot telling the church to return their ten days. But it was a must to change the calendar because a calendar is only useful to index seasons. And in the Ethiopian case, it's much simpler because our calendar is even older than Julius calendar and has more accuracy. And as most of you have guessed, it was created by the Ethiopian Orthodox Tewahedo Church. The study of the Ethiopian Calendar is called "#Bahire_Hasabe". #Fact the formula found on #Bahire_hasabe can let you calculate precisely when Gena Beale (Ethiopian Christmas) will happen after a 1000 years. #Bahire_Hasabe has astrological studies which could point you to another book of study of Ethiopian Astrology called "#Awde_Negeste".