Jaehaerys I, the longest reigning Targaryen monarch in Westerosi history, was a dragonrider and he was also known as "Jaehearys the Wise".
A picture of the leaked clipping titled "Bran's sitting on a huge secret" was posted in the GOT fangroup/r/Freefolk Thursday.
Although the factoid is not confirmed by HBO, it makes way for several theories about Kit Harrington's brooding Lord Commander.
Jaehaerys II was Jon's great - grandfather.
So per Empire, Jon's real name is Jaehaerys Targaryen.
Could it be true? Not so much because of the intricate Game of Thrones mythology, but because the name Jon Snow just sounds so much folksier than Jaehaerys Targaryen. In its current issue, the magazine wrote, "As "Game Of Thrones" embarks upon its penultimate season, we head to Westeros to learn 15 things from the cast, from Targaryen to Lannister and everything in between". "'Bran's now in this precarious situation in which it's just him and Meera [Ellie Kendrick], and he has all of this information that could change the entire story", says Hempstead Wright. But when Lady Lyanna whispered his name to young Ned, only "His name is..." was audible leaving the name blank, Cosmopolitan added.
Assuming that it's true and HBO have let it slip, rather than Empire just seeing it on forums and believing it to be correct, the big question now, then, is just whether Jon will find out during Season 7, and what it'll mean when he does.
A season 7 spoiler from the /r/ASOIAF subreddit, reveals Jon Snow's real name. Fans assumed they would have to wait a while before learning Jon Snow's real name, but thanks to an eagle-eyed Reddit user, it looks like we have learned the truth earlier than we expected. "'He knows all about the White Walkers too'".
I do post about Ice & Fire and GAME OF THRONES whenever there is actual news to report.
Jaehaerys Targaryen is definitely an old Targaryen family name. He died at the age of 37 and was the sixteenth Targaryen king to sit the Iron Throne. Moreover, Rhaegaar may have wanted to gift his son a pleasant name and that is his great-grandfather's name. Jaehaerys restored stability to the realm, ended the Blackfyre threat during the war of the Ninepenny kings, and improved relations with the major houses who were unhappy during his father's rule (Aegon V - Egg, the brother of Maester Aemon).