Podrick’s song on last night's Game Of Thrones is riddled with Westerosi lore

[Spoilers for season 8, episode 2 of Game Of Thrones]
Toward the end of last night’s stellar episode of Game Of Thrones, Podrick Payne (Daniel Portman) treated fans to a somber rendition of a little Westerosi ditty called “Jenny’s Song.” For most viewers, this sad melody played over glimpses of all our heroes preparing for battle (and perhaps death), evoking The Lord Of The Rings’ Pippin singing “The Edge Of Night” before the Battle of Osgiliath. As a new article from Vanity Fair points out, there’s more going on here than mere tone-setting. This particular song contains a lot of hidden meaning for book readers and has direct ties to the personal histories of the show’s lead characters.
In George R.R. Martin’s A Song Of Ice And Fire series, “Jenny’s Song” is a personal favorite of the Ghost of High Heart, a mysterious old witch who trades songs for prophecies. The Jenny in the song is the witch’s old friend, Jenny of Oldstones, a woman of low birth who, once upon a time, married Prince Duncan Targaryen, leading the prince to abdicate the throne and allow his brother, Prince Aerys a.k.a. the Mad King, to become the ruler of the Seven Kingdoms. We all saw how that turned out.
The connections don’t stop there, however. The Ghost of High Heart is also believed to be the woman who first prophesied that the Prince That Was Promised (a.k.a. the savior of Westeros) would come from the line of Areys and Rhaella Targaryen, who are the parents of Dany and Rhaegar and grandparents of Jon. When Prince Rhaegar learned of this prophecy, he became a little obsessed and, as Vanity Fair notes, may even have been the one who wrote “Jenny’s Song.” It’s said in the book that Rhaegar and Lyanna Stark first fell in love when Rhaegar played a song at the Tourney of Harrenhal that made Lyanna weep. It’s possible that song may have been the very same one we heard last night.