The Age of Wars was a very violent period in Krypton's ancient past. Although the underlying factors that led to the Age of Wars had been building for years, a Kryptonian warmonger named Jax-Ur initiated the conflict by invading the province of Nol-Yan that became the catalyst, in which Jax-Ur ensured in keeping the conflict ongoing.
The period ended when twelve telempaths, widely known as the Twelve Wise Ones, led by Von-El seek to break the cycle of war. The warring factions were brought to a temporarily truce during the Seven Army Conference – the last peace-talk in the Age of Wars – in which it was where the Twelve first met. At the conference, Von-El advocated for an end to the conflict that is reinforced by his honored and former enemy, General Rol-Zod. Nearly the entire assembly followed their caused, except for Jax-Ur.
The Age of Wars came to an end at a final battle between the armies that supported peace known as the Seven Armies, led by Von-El and Rol-Zod, and Jax-Ur, which ultimately saw the latter's defeat. Following Jax-Ur's defeat and subsequent banishment, the Age of Wars ended and ushered Krypton's golden age, putting an end to the chaos that had gripped Krypton for so long.