The ancient Greeks dated years from the (mythic) foundation of the Olympic Games.
The ancient Romans dated years from the (mythic) foundation of the city of Rome.
We, however, date our years from the (mythic) birth of Christ.
Call it “Common Era” if you like, but clearly we need a more fitting way to count sacred time. We need some other pivotal mythic event from which to number our years.
For my pentacles, the best proposal to date comes from Merlin Stone's seminal 1979 essay “9980: Repairing the Time Warp,” in which she proposes that we date our old-new year-count from the beginning of agriculture.
For better and for worse, agriculture has changed everything that came after it. It's an event of both historic and mythic proportion. Better yet, it's something that we all share.