Timeline

100,000 years ago: The Forerunners disappeared from the galaxy. No records of them exist or are referenced in any materiel that the Allied Forced have given to the Terran Federation.

14,000 years ago: The Prime Forge was found and taken by the first Magisters.

13,000 years ago: Derivative Forges began and finished production around this time (Atlantis finished being built on Earth around 12,988 years ago).

12,500 years ago: Atlantis Forge left earth

10,000: Atlantis, while in the Darius System, finished it's final mobile armor, and one Mobile Armor was left behind to guard Atlantis Forge while the rest were shiped to various places in the Local Group. One month later, that mobile armor and all others went rampant, for seemingly no reason. A further month later and the mobile suit project is formed and fielded, and the Mobile War commences. After the near destruction of the Elven people, most of the Mobile armors were defeated and the Elves were able to rebuild. The war lasted 5 years.

800 years ago: the covenant-allied forces extinction war began.