King Harys' Folly is a song which Beren Merryweather claims as his own, though few truly believe that he wrote it. The song gives the details of the events leading up to the sack of King's Landing.
Lyrics
The stag was smitten of the rose, so when she did go missing
He called his banners ‘gainst his foes, to counsel he did not listen
A Baratheon's heart is true and true but oft leads him astray
And that is why King Harys flew, with his whole army away
They marched in strength to find this flower, love blinding his reason
Believed his maiden in High Tower, suspecting lies and treason
But while they swarmed outside Old Town, and rallied at its gate
The lion, from his rock crept down; King Harys took the bait
By land and sea his foes they poured, but they weren't unopposed
In their way a single lord, the brother of Dragonstone
Though he knew the city sacked, the stag raised Antler high
The Baratheon bear, strong and brave, was unafraid to die
The brother fought but he was slain, caught in lions jaws
The King continued to search in vain, for his rose, his Lady Maude
The landing fell, a king was crowned, before sun could rise again
The throne was bloodied, a corpse was found, so ended Blackfyre reign
But twas the plan (though few had known, how masterfully it was done!)
For there upon the Iron Throne, the lion placed his son