Although there were several battles on Bir'tedor in the civil war that followed Kracor's (Hogas') conversion to the Jedi, this one was given the title it has due to its enormous effect.
After a month of rebellion by the pro-Sith rebels led by Admiral Korth, Hogas' troops were finally positioned for one last battle to decide the war. Over three million of his men surrounded the rebels' one million man army led by Lord Synyster on the Plains of Garbosa, where the battle took place. After eight hours and over a million deaths, a truce was made. Two days later, the armies were reunited under one flag, aimed at rebuilding relations with the Sith and destroying the ties with the Galactic Alliance.