Since the beginning of time, Westeros has been inhabited by the Children of the Forest — a mysterious and magical non-human race that worshipped the Old Gods. The Children of the Forest lived off the land of Westeros for thousands and thousands of years, before any humans arrived to the continent.
As their name suggests, the Children of the Forest had a special relationship with the weirwood forests. To the Children, these forests were sacred and magical. The weirwood trees were considered to be gods to the Children; supreme spiritual entities with which the Children shared a magical relationship. The Children would carve faces into the weirwood trees, and it is said that after the Children passed on, they could still connect with the forests by seeing through the eyes of the faces carved into the weirwood trees. When the weirwood trees bled their red sap, it was believed to be the tears of the Children of the Forest.
The Children are described as being very small, dark and beautiful. They spoke a different language, the Old Tongue, and they lived in the forests, rather than out in open lands. They had a deep connection with mother nature, especially the forest, from which they derived their magic. They had no need for material objects and got all that they needed from the land.
Connecting deeply with mother nature, the Children were skinchangers, possessing the ability to enter the minds of the animals around them and control their actions. The most powerful of these Children were also called Greenseers; they were considered to be shamans of the Old Gods. In addition to skinchanging, Greenseers also possessed the magic of greensight — a power of prophetic visions that show what is to come.
Today, the people of the North have a special respect for the forest; it’s weirwood trees are spiritual and in the North they still pray to the Old Gods. These customs and religious practices can be traced back thousands of years to the Children of the Forest and the First Men who adapted their ways.