Once, the Kingdom of Cormanthyr was one of the greatest Empire of Elvenkind since the Crown Wars. Once, the humans of the Dalelands and the Elves of Cormanthyr signed the Dales Compact and raised the Standing Stone, marking peace and cooperation, even unity between the elves of Cormanthyr and the humans of the surrounding lands. Once, the city of Myth Drannor was a mighty, cosmopolitian city of wonder and wealth, the beating heart of Cormanthyr.
Then it all came to an end - though officially the Kingdom of Cormanthyr didn't die until 1344 DR, with the declaration of the Retreat, the loss of Myth Drannor after the Weeping War in 714 was the death knell for the Kingdom. Slowly, the elves abandoned more and more of the forest, and eventually left entirely. Humans and monsters began to move in, as did Drow of all stripes, but especially the followers of Vhaeraun. Sembia and the Zhentarim could eye the Dales without fear of elven interference.
And then, in 1374 DR, amidst a war against the demon-blooded elves of House House Dlardrageth, elves returned to Myth Drannor en masse, sparking a yet wider war that drew in Lolthites, followers of Vhaeraun, the Zhentarim, Hillsfar and Sembia.
The year is now 1377 DR and an uneasy peace now reigns in Cormanthyr. All sides now spent by bloody war, everyone jockeys for position and influence. Cormanthyr has ruined settlements and sacred spaces to reclaim, loose monsters and demons to clear out, and hostile or suspicious neighbors to watch. Even the Dales, once the closest friends of Cormanthyr, are not all enthused about their old neighbors and benefactors returning. A new Coronal, Ilsevele Miritar, reigns for the first time since before the Weeping War, but the Kingdom is still rebuilding, rather than rebuilt. Tensions within and amongst elvenkind boil under the surface, and no one 'defeated' in the Cormanthyr War - nor others with their eye on the region - is content to do nothing while a potential new threat to their interests and goals grows more powerful in the forest of Cormanthor.