In Krypton's ancient past, the planet was embroiled in a greater conflict known as the Age of Wars. Out of the war were twelve Krpytonians led by Von-El. These twelve were telempaths who have the ability that allows them to understand the minds and hearts of others, and used their special gifts in mending peace.
The twelve were then dubbed as the Twelve Wise Ones for their great wisdom and understanding their fellow Kryptonians, enabling them to negotiate peace. The Twelve were originally gathered at the Seven Army Conference and subsequently led the Seven Armies against Jax-Ur, which saw the end to the Age of Wars.
According to legends, at the end of negotiations, Von-El threw his blade into the sky, and told his fellows to do the same. That day marked the end of all warfare between the people of Krypton. The Twelve went on to form Krypton's ruling body, the Council of Twelve, which ensured that all of Krypton had peace and prosperity for all time.