The Kasethean Calendar is used mainly on the western continent(Qiswa), in O'koll, Oymun, and on most of the Yesh'na isles.
The beginning of recorded time, many hundred years ago, was placed to be when a Fui Ley Goliath climbed Mt. Lea'jo and saw The Harvester, the god of harvest, where he told him that the best harvest of all time would be granted to him if he spread the word.
This first interaction with the gods in all of the continent sparked the need to mark the historical day and even though many of the countries following the calendar have other religions, they all agree that it is a practical way of evolution and should not be dismissed.
AH - Ante Harvester
PH - Post Harvester