The Thaw, also known as the Flood Ages, is an era in Dominaria's history that began with the casting of the World Spell by the planeswalker Freyalise. Little is known of what happened in this era save for the continent of Terisiare, where powerful alliances sprung up in the wake of the Ice Age's ending and Lim-Dûl's defeat. Kjeldor and Balduvia came together as the kingdom of New Argive, while the elves of Fyndhorn migrated to their new home of Yavimaya.
The Thaw was a time of great upheaval. Only some areas of Terisiare, including the kingdom of Almaaz, were unaffected by great floods which destroyed vast stretches of the continent, splitting it into an archipelago of large islands. Disease flourished due to the higher temperatures, and plague spread across the southern part of the continent, especially in the city of Krov. The machines of Soldev rose up against their masters, destroying the once-great city and scattering its people.
Shortly after the World Spell, the Cult of Rimewind, led by Heidar, tried to halt and undo the Thaw with their ice magic, but ultimately failed due to the alliance of New Argive and Yavimaya, as well as treachery within their own ranks. Following this conflict, New Argive's control over the continent was secured, the Order of Stromgald was finally defeated, and relative peace reigned in Terisiare until the Apocalypse.