Game Of Thrones: 7 Fan Theories About Jon Snow 's Parents (That Aren't R+L=J)

Given the textual evidence, all of the "promise me, Ned" memories and the Tower of Joy, there is a strong chance that Lyanna Stark is really Jon Snow's mother, which is partly why R+L=J is such a popular theory in the first place. This one continues that line of thinking, but instead of Rhaegar it has Arthur Dayne as the father. 

Dayne was a legendary knight in Westeros, and a member of the Kingsguard posted outside the Tower of Joy to look after Lyanna (and her unborn baby?). He was killed in the battle with Ned's men outside the Tower, and afterwards Ned went to Starfall to return Dayne's sword. 

Arthur could have been the one who Lyanna actually fell in love with, and that Rhaegar did what he did out of loyalty to his closest friend (or they fell in love after the kidnapping). It prompts the question of why Ned would lie about it, but that could be to protect his hero's noble image, or for the sake of his sister Ashara. It fits with the timeline, and raises the possibility of Dawn, Dayne's rather epic sword, being Lightbringer with Jon as Azor Ahai Reborn.