Bran Stark: He needs to know the truth.
Samwell Tarly: The truth about what?
Bran Stark: About himself. No one knows. No one but me. Jon isn't really my father's son. He's the son of Rhaegar Targaryen and my aunt, Lyanna Stark. He was born in a tower in Dorne. His last name isn't really Snow, it's Sand.
Samwell Tarly: It's not.
Bran Stark: Dornish b*stards are named Sand.
Samwell Tarly: At the Citadel, I transcribed a High Septon's diary. He annulled Rhaegar's marriage to Elia. He wed Rhaegar and Lyanna in a secret ceremony.