Despite being married to Cersei, Robert continued to pine away for Lyanna Stark, who had died shortly after being abducted (or was she?) by Rhaegar Targaryen. Cersei, once excited by the prospect ...

Some fans think that Benjen Stark knew the truth behind Lyanna's abduction and Jon Snow's parentage. Lyanna willingly eloped with Rhaegar Targaryen, unbeknownst to everyone outside their union.