Taken from "History and culture of the Sunset Kingdoms", by Jaqen Wunel, Pentoshi scholar

Chapter 2: The Kingdom of the North

Although not as rich or densely populated as other parts of the continent, the region simply known as "the North" has its own interesting and unique history...

...Right before the Andal invasion, the North was divided into three different realms: the Barrowlands, ruled by House Dustin of Barrowton; the Winterlands, ruled by the now extinct House Stark of Winterfell; and the Red Kingdom, ruled by House Bolton of the Dreadfort. Although nearly equal in size and power, over the centuries the Red Kingdom managed to prevail upon its neighbors. House Stark was completely wiped out by King Royce IV Bolton, also known as "Red Arm" for his habit of pulling out his enemies' entrails with his bare hands. The Dustins, on the other hand, were able to stand on their own until the arrival of the Andals, when they were forced to ally with the Boltons to repel the invaders. Later, they would submit to the Red Kings (1), thus completing the unification of the North...

...In an interesting parallel with one of its southern neighbors (2), the North is almost completely homogenous. Ethnically, most of its people can claim to be of pure First Men blood; religiously, they worship the Old Gods of the forest, the only exception being the Manderlys of Moat Cailin (3) and the people of the Three Sisters, who follow the Faith of the Seven...

...Most criminals have a choice of joining the brotherhood of the Night's Watch or being beheaded. However, the worst of them aren't given such an option, instead being sent to the Dreadfort to be flayed alive. This barbaric practice is an ancient tradition of the Boltons, and it is said that they keep the best skins to make cloaks or boots (4), while in some cases they just hang them as a warning to criminals and hostile foreigners (5)...

...The North is virtually unassailable from land, for the swamps of the Neck are nigh to impossible to cross without already knowing a safe path, and there is a good reason if the ancient stronghold of Moat Cailin is sometimes called "the Graveyard of Armies".

The sea would be a safer bet. The North never had a strong fleet, unlike the Iron Islands or the Reachmen of the Arbor, traditionally favoring infantry and cavalry. However, any invader would eventually have to land, and they would soon be met by the northern forces. Particularly, Houses Redpine of Bear Island and Redwater of Redwater Town (6), both Bolton cadet branches, have made a name for themselves over the centuries by brutally dealing with any would be invaders...

(1) The reasons for this are not clear. Some people think that it was a tactical choice, born of the realization that an enemy like the Andals could only be defeated by a united front. Others, like yours truly, are of the opinion that the Dustin forces were so depleted after the end of the war that they couldn't even hope to keep the Boltons at bay in case they turned their eyes on the Barrowlands.

(2) The Vale of Arryn, with its many houses of pure Andal blood.

(3) Originally from Dunstonbury in the Reach, the Manderlys fled to the North after a dispute with a rival house. They pledged fealty to the Dreadfort and were given the lordship of Moat Cailin and the Neck, to act as a shield against invasion attempts.

(4) The current Bolton king is said to wear an old cloak made from the skin of the last Stark prince.

(5) Although thousands of years have passed, the memory of the so called "Pink Wall" is still alive. After defeating the Andal invaders, King Belthasar III Bolton had the surviving Andal prisoners flayed, and their skins were later placed on strategic points along the eastern coast of the North.

(6) Redwater Town, located at the mouth of the river known as White Knife, is the largest settlement in the North.