The Great Exodus marked a new era for the Zambasonian people when the gods decided to leave the earth, and although no one was awake to witness it, at the dead of night, it is said that a great light shone down upon the Deenja island. The Great Exodus is, thus, also called the Illuminated Night.
The calendar is based around the moon Juliente, or Kielon as it is known in the east, and every new moon, a new month starts, as it was calculated that the IN happened during a new moon, which also fits with old descriptions detailing a "moonless night with no stars on the horizon" although the sources are questionable.
The Great Exodus was, however, an event that came to affect the whole world beyond just Zambaso. When the gods left the mortal realm, they took with them most of the magic that had been freely available to everyone and everything and left only hotspots scattered around the realm. These deposits of magic were soon monetized and refined magic has become the primary currency there.
Before this, the currency was mainly gemstones, favours, and bargaining, as the caster's magic was replenishable and the natural flow of magic seemed endless.