Here's some more awesome stuff since I mentioned the ghost of high heart. And the backstory is partially why podricks song is my favorite scene in the show
View: https://youtu.be/ZCnEJYds1iA
King Aegon V was the man nicknamed Egg as a kid, which is the name a dying Maester Aemon kept yelling out in delusion. "Egg! Egg!"
Aegon V had been raised by the hedge knight, ser Duncan the tall. So he named his eldest son Duncan. Prince Duncan chose to renege on a betrothal to a Baratheon, which caused a short rebellion, which Duncan the tall (commander of th3 kings guard) ended by defeating Ser Lyonel Baratheon in single combat
Prince Duncan chose to give up his right to the throne because he had fallen in love with a commoner named jenny who was friends with the woodswitch. The ghost of high heart
Then the Tragedy at Summerhall.
Details are not clear, but it seems King Aegon V may have been trying to hatch dragon eggs with wildfire. And they exploded. King Aegon V, prince Duncan, and others died.
Ser Duncan the tall died, but not before saving some people. One of those people may have been future mad King aerys wife. Outside Summerhall, she gave birth to Rhaegar as the building burnt and people died
The Tragedy at Summerhall
Prince Duncan died. And presumably, that's when Jenny died
The woodwitch asked one of the brotherhood to sing Jenny's song every time they stopped and saw her in the books
So that's extra color on why that song is so sad. And major props for that song montages to close out the second to last scene before the Long Night episode
Actually, it's even cooler. The show deserves more credit
Earlier in that scene, Jaime had dubbed Brienne "a knight of the seven kingdoms." That is the title of the "dunk and egg" novella series.
And it just so happens that there is a subtle clue in the books that Brienne of Tarth's is a descendant of Ser Duncan the tall (her father has his shield hanging in their hall)
So the show had Jaime dub her the knight of the seven kingdoms. Then Podrick busts out Jenny's song, which is based on the event in which her ancestor - Ser Duncan the Tall - the knight of the seven kingdoms, died.