When Jon Snow was 14 years old, he was discovering his new identity as a warg. He had seen Brandon Stark's dying when he fell from the Broken Tower, and this changed Jon's personality in the following weeks. He started delving into his warg and Skinchanging gifts and he soon learned to Skinchange into animals and birds.
It was when Bloodraven, the Three-Eyed-Raven, learned that Brandon had not survived the fall from the Broken Tower, that he finally sought out Jon. Unwilling to be manipulated by someone who only saw power, Jon refused the summons and chose a different path. Instead of following Bloodraven, he chose to explore the outside world.
Jon eventually found himself in Essos. He worked odd jobs, first as a coin counter and then as a sellsword, but his thoughts were always of discovering more about the gift he had. Then, on a fateful day, he purchased a petal of a weirwood tree from Skagos. Upon further research, he learned that blood could help the tree grow and larger. He saw an opportunity to further his goals of uncovering the secrets of his warging and decided to feed the tree the blood of criminals.
With the blood nourishing the tree, it grew in a matter of two years. Jon then placed his hand on the tree and in doing so he was able to leave his body and enter the inky place which houses memories of past ages. It was through this place that Jon was able to see his direct ancestry, going back as far as Brandon the Builder.
Jon soon found himself at the court of King Jaehaerys Targaryen, who wanted to send his daughter Viserra to be wed to Jon's ancestor Ellard Stark. Before the King could complete his arrangement, Bloodraven, who had been watching Jon's progress, appeared. He warned Jon that messing with time could cause unimaginable outcomes but Jon refused to listen. In a fit of rage, Jon and Bloodraven engaged in a battle of wills in the inky place between time and space .
With his determination and strength of will, Jon was able to overpower Bloodraven. He used his Skinchanging to take control of the foolish King and force him to go through with what he had started. When Bloodraven raged Jon Snow stood before him he smirked and said " listen you Redworm you seem to liking being the strongest Warg and serve your incestuous Valyrians but now a Stark has come to benefit his House and you seem to forget that you have First Men blood and linger to your Wyrm Valyrians,how did gain your greensight from the First Men,well I didn't and if you interfere in my plans again I would whipe the floor with you and make your precious House Targaryen extinct." So he finally admitted defeat and left Jon .
Jon would return to the land of the living, the only thing that remained was the memory of his triumph over Bloodraven and this discovery had brought him closer to unlocking the secrets of his warg and Skinchanging gifts.