Griffin Kingdom of the Hill

The Griffin Kingdom of the Hill, or the Redsmith Confederacy, is the coalition of Mountain Clans within the mountains of the Vale headed by Donnahal Uthelhain, Chieftain of Clan Redsmith and Grififn King of the Hill. They claim to be the rightful rulers of the Vale Proper through ancestry to Robar Royce, the last High King of the First Men in the Vale, as well as the mythical Griffin King of old.

Origins
The foundation of the Hill Kingdom can be traced back to the Andal Invasions of Westeros, when the First Men of the Vale were forced to flee into the Mountains of the Moon to retain their independence from the newly-created Vale of Arryn and the Falcon Kings who ruled it. The next few thousand years would be spent attempting to rebuild what had been left behind in the fertile valleys of the Vale Proper, only to fail as the rocky terrain failed to truly sustain the Clans who then resorted to raiding the Lowlands and weaker tribes. Even with the arrival of more Essosi invaders from across the sea did little to change the ways of the Mountain Clans.

It was only with the War of the Crossing that the situation began to change. With the introduction of proper castle-forged steel, as well as the same tactics that had won the Andals the Battle of the Seven Stars, the Mountain Clans of the Moon began the slow process of regaining the strength they had once boasted. Though, it was only after the Battle of Strongsong that the confederacy was truly born-- for, during the raids that ravaged the Lowlands, a longtime plan between the Royces of Runestone and Clan Redsmith was coming to a head. Through events not known to the Lowlands or the rest of Westeros, save the Royces, Donnahal Uthelhain united the Clans behind the Griffin Banner for the first time in centuries, and the Kingdom of the Hill was (re)born.

Recent History
The Abduction of Artys Arryn was an event pitting the Hill Kingdom against the Vale of Arryn which resulted in the abduction of the Lord Paramount as well as most of his immediate family.