Border Wars
The Border Wars<ref>Border Wars is a proper noun in Transformers: The Ultimate Guide "Civil War," (Timeline sidebar) p15. 1st edition, 2004.</ref> is the designation for a series of internecine conflicts 7.4—-6.5 Million Years ago on Cybertron when both the Autobot and Decepticon factions fractured into multiple warring sub-factions.
Broadly speaking the Border Wars began shortly after the disappearance of Optimus Prime and Megatron 7.4 Million Years Ago. The rogue ancient Transformer The Fallen claimed responsibility for Cybertron's subsequent plunge into the Dark Ages, slowly pushing events towards ever-increasing chaos over the course of almost a million years.
After The Fallen's defeat 6.5 Million Years Ago, the Border Wars continued<ref>Introductory blurb, "The Age of Wrath", 2004</ref> for approximately 500,000<ref>Transformers: The Ultimate Guide "Civil War," (Timeline sidebar) p15. 1st edition, 2004.</ref> years, lessening in intensity as the Autobots unified under Ultra Magnus. Their end is marked by the peace treaty (and subsequent massacre) at Tyger Pax 6 million years ago.