Unification of the North

The Unification of the North was a process that traditionally lasted for two milennias, in which House Stark gradually repelled Ironborn invaders and subdued Northern rivals, particularly House Bolton. The countless wars saw the birth of the Kingdom of the North, which would last until the War of Conquest more than 6,000 years later.

History
In the Age of Heroes, The North was divided between several petty kingdoms. The Winter Kings of Winterfell and the Red Kings of the Dreadfort were the most powerful of them all, and their rivalry resulted in countless wars over a period of several centuries. These wars were decidedly indecisive, and the Boltons killed several Starks in this period. The Boltons also earned themselves a sinister reputation for flaying their enemies, a practice that eventually made itself to their sigil.

Internal Northern wars had the effect of opening the North for pirates and raiders as well. King Jon Stark captured White Knife from Sistermen pirates, and his son Rickard Stark defeated the last Marsh King and brought The Neck into the fold. King Rodrik Stark won Bear Island from the Ironborn by wrestling a leader of House Hoare, although the date of this event is unclear. Bear Island was subsequently gifted to House Mormont.

Due to their inferior numbers vis-a-vis the Starks, the Boltons were eventually defeated. The last Red King Rogar Bolton bent the knee to House Stark, who later banned their gruesome practices. This marked the birth of the Kingdom of the North.



Aftermath
The Boltons bent the knee just in time for the North to face the Andal Invasion united. The Starks, the Boltons and other Northern houses faced Andal invaders at Moat Cailin countless times, defeating countless invasions together. This joint effort did not result on harmony between the Northern houses; the Boltons rebelled against Stark rule several times, though the Starks put down every revolt.

The bad blood between the Starks and the Boltons persists 6,000 years later. The Boltons were one of the orchestrators behind the Red Wedding, which saw the fall of the newly-reborn Kingdom of the North and the death of King Robb Stark. The Boltons were defeated for good in the subsequent Battle of the Bastards, in which the remainder of the Stark family retook Winterfell and killed Ramsay Bolton, the last Bolton alive.