War of Tears
Common name for the Elvish Civil War that occurred some 30 millienia ago, and resulted in the destruction of the Elven Empire, its capital Eldamar, significant damage to much of Alusia, and the consumption of considerable mana.
Little is known about the original causes of the Civil war as all those at the heart of the Empires politics did not survive the ensuing conflict.
The war's major outcome was the splitting of the elven race into various sub-races (see Drow and Erelheine). At the time of the war the Demons and Angels also appeared and there is much debate among philosophers if this may have been a cause of the conflict or fallout from it.
Either way the way was bloody and savage and hundreds of thousands of Elves lost their lives fighting their own Kin. Whole continents shifted, forests burned and the scars on the land still remain to this day in many parts of Alusia and Terranova.
Reference: War of Tears