Forgotten Realms has a long, detailed history. The Forgotten Realms Wiki and The Grand History of the Realms provide excellent resources for this. Any canonical events in or after 1479 DR are not necessarily part of this setting. The stories below are not part of the Forgotten Realms canon and so will not appear in other sources, but they are part of the backstory for our campaign, so you can draw upon them as you like.
Marking the Years
You’ll find dates throughout using three different calendars. The first is the most commonly used throughout Faerûn, a list of names for each year supposedly first written by Augathra the Mad. They go from -422 DR to what will be 1600 DR (The Year of Unseen Enemies), although it is widely believed that the roll of years was created by Alaundo of Candlekeep. Because some of the names of the years went missing, Alaundo replaced these with his own choices. Supposedly, the names given the years are prophecies made by Alaundo as to the most significant event of that year.
However, numbers are often easier for sages, scholars, academics, and scholars, and so a number of other calendars exist in Faerûn. The Northreckoning (NR) dates from the year Ahghairon became the first Lord of Waterdeep. Waterdeep’s importance in trade up and down the Sword Coast has made this the most popular means of counting years in the region, though there have always been some who have considered this the height of Waterdhavian arrogance. That argument has found some supporters recently in Neverwinter, particularly among the Sons of Alagondar.
The third system is the Dalereckoning (DR) is taken from the Year of Sunrise, when the Standing Stone was raised by the elves of Cormanthyr and the human Dalesfolk. It is the most widely used system in Faerûn generally, though not as popular as the Northreckoning in Neverwinter.
The reign of Nasher Alagondar is remembered as a golden age for Neverwinter, but the Wailing Death stands out as a dark chapter in that history. Ander Brightwood emerged from that chaos to become the Hero of Neverwinter. However, the official histories often neglect the tragedy that drove Ander, his love for the story’s greatest villain: the blackguard Aribeth de Tylmarande.
Neverwinter Nights II
The destruction of his hometown in the Mere of Dead Men pushed Bran Farlong to Neverwinter and revealed his connection to the King of Shadows. In his adventures he rose to become one of the Neverwinter Nine. After the defeat of the King of Shadows, he was swept away to distant Rashemen, where he was cursed by the Spirit Eater and joined the Betrayer’s Crusade to tear down the Wall of the Faithless, ultimately leading to the Spellplague and the reordering of the cosmos.
The Spellplague had isolated the remote barony of Mornskeep in the Farsea Swamp from the rest of Cormyr, but only when Baron Huron Dundragon III, his twin sister Fiona, and their dragonborn half-brother Torinn freed their remote barony from the tyranny of a black dragon did they discover just how much. The return of Mornskeep brought about the Shadow War, but also proved vital to Cormyr’s victory.
The Fian of the White Dragon
In the wake of the Shadow War, Cormanthor recruited bands of adventurers to patrol their forest. One such band, the Fian of the White Dragon, found itself pulled into the Feywild, where the Prince of Frost manipulated them into bringing about the destruction of Mithrendain, the Autumn City. As the Prince of Frost began his war to conquer the Feywild and wipe out all life on Toril, the Fian pushed into the Vale of the Long Night, where they confronted the Prince of Frost and ended his reign forever.
The Lost Crown of Neverwinter
The appearance of the Lost Heir of Nasher Alagondar stirred up many in the city recently as he heroically saved the city from plaguechanged monsters that Dagult Neverember seemed powerless to stop. As time passed, however, the Heir descended into madness, and began unleashing monsters on the people of Neverwinter. It fell to her sometimes companion and ally, Ammon Hornraven, to stop her.
The Sage of Shadowdale was driven mad by the Spellplague. He believes that Mystra was not killed by Cyric at all, but merely deeply wounded and forced into hiding. He felt her presence and discovered her when no one else could. Fighting through hell and death, Elminster faced his greatest enemies, like Manshoon, and, defeating them one by one, gathered up all the silver fire that Mystra had granted to her Chosen, and brought them back to her so that she could be restored and set everything back just the way it was before the Spellplague.
Of course, this is nothing but Elminster’s self-serving delusion. Mystra died, and there is no putting the world back to the way it was before. The Sage of Shadowdale is a broken man, insane but still wielding enormous arcane power, and all the more dangerous for that. He is a madman with nearly godlike power and utterly delusional.