Forgotten Realms - Rites of Ascension
Cormyr was founded in 26 DR. Its first king was Faerlthann Obarskyr, son of Ondeth Obarskyr and Suzara Obarskyr. The kingdom was initially formed because the elves and humans in the region needed to get along with each other. Since that time, Cormyr has grown by absorbing the realms of Esparin and Orva and claiming the Stonelands as its own.
Some time between 376 DR and 432 DR, Cormyr was invaded by many dragons, including Thauglor, who laid waste to virtually all of the settlements in the country. It was then raided by orcs from the Stonelands, who occupied the King’s Forest until they were finally driven out in 429 DR by King Duar Obarskyr. By 432 DR, many noble families had left Cormyr for either the Dalelands or Waterdeep, or split into small factional bands. The city of Suzail was sold to Magrath the Minotaur and his pirates by a traitor to the crown around this time, and it was after Magrath’s death that the Purple Dragon was adopted as the nation’s official symbol.
In 1352 DR (the Year of the Dragon) Gondegal, also known as “The Usurper King” and “The Lost King”, attempted to establish a separate kingdom centered on the city of Arabel. He was overthrown, after only eight days in power, by an allied army composed of forces from Tilverton, Sembia and Daggerdale, along with the Purple Dragons, led by king Azoun IV.
Shortly before the Spellplague, the Goblin Wars (1370 DR-1371 DR) did significant damage to the kingdom, and internal and external struggles threatened to tear the kingdom apart. It was only through the Treaty of Phsant that Cormyr was able to end the Goblin wars.
In post-Spellplague times, the influence and reach of Cormyr has changed somewhat. Cormyr now controls the part of the Dragon Coast between Easting and Westgate, including the cities of Proskur, Priapurl, Elversult, and Teziir. Cormyr has also gained a stronger presence in the west. Maloren’s Rest is Cormyr’s foothold in the Tunlands. Troops in Castle Aris help goods pass safely through the Farsea Swamp on their way west. In the East, Highdale is now a protectorate under crown rule. Daerlun once welcomed the protection of Purple Dragon troops, but gained its independence from both Cormyr and Sembia about forty years past.
(this information is provided by the folks at http://forgottenrealms.wikia.com/wiki/ ).