The Age of Myth was the golden dawn of the Mortal Realms, the era that followed the death of the World-That-Was and the settling of the eight realms into their elemental forms. In this age Sigmar walked among mortals, gathering the wandering gods and founding great civilisations of wonder. Cities of gleaming stone rose from the wilds, pantheons were forged, and the tribes of men, aelf, duardin and their kin flourished beneath the protection of divine patrons.
It was a time of miracles and monstrous folly alike. Sigmar bound the seraphon and other ancient powers into his Grand Alliance, and mortal empires spread across every realm. Yet hubris festered beneath the splendour, and the pacts that gods made with darker powers sowed the seeds of ruin.
The Age of Myth ended when the compact between the God-King and the Dark Gods collapsed, and Chaos poured unchecked into the realms. What had seemed an eternal golden age proved but a prelude, remembered ever after as a paradise lost to the Age of Chaos.