Icelost Years

Less than two years into Zan's reign, Errevon the Rimelord, taking advantage of another celestial solstice, opened a rift from the Frostfell, the elemental plane of ice, to what will later be called the Frostweald. With an army of frost giants and sentient blizzards, Errevon conquered most of the continent in a few years.
The Council of Tal'Dorei convinced Syngorn and Kraghammer to join in an alliance against Errevon, and together their forces battled Errevon back through the rift, which the Ashari druids sealed shut. The victory was later celebrated annually as the Winter's Crest festival.