Literature
Sonic X Timeline (Before the actual story)
Sonic X Timeline
*Before Sonic and all existed*
Unknown B.C.: At some point, a world was split into two with one going by the name Earth and the other going by the name of Mobius which was then put into another universe. Also was given to Mobius was the Planet Egg which helps the world and many others sustain life.
4,000 B.C.: On Mobius, a warring civilization of Echidnas, the Knuckles Clan lead by their leader Pachacamac, attempted to steal the Chaos Emeralds from the Chao at the shrine of the Master Emeral