The Turning War was a five year uprising by the humans, led by the Dragon Masters, against the Dragon Kings. The humans came close to victory until Azran Bedlam betrayed them in his own quest for power. All of the Dragon Masters were killed accept Lady Gwendolyn, who was frozen in amber by Azran. At the very end of the war Nathan Bedlam was able to slay the Purple Dragon, but was killed in the process.
While the Turning War ended with defeat for the humans, it was the first significant step toward their liberation. The Purple Dragon's death left Penacles undefended, allowing the Gryphon's mercenary band to liberate the city. Moreover, Purple was the strategist for the Dragon Kings, a loss from which they never recovered.