A Great Zero is a point within every new Age. It was set by the Ronay and D'ni Surveyors who first explored the Age, and established it usually on a prominent natural landmark. From the Great Zero a line was drawn, usually toward magnetic north or another prominent landmark, to aid in exploration, navigation, construction, etc. It was during Tevahr's reformations when King Rakeri announced that the old line was accurate and should be honored again.