What is the Blackfyre Rebellion and why is it important to A Knight of the Seven Kingdoms?

A Knight of the Seven Kingdomsis a highly faithful adaptation of George R.R. Martin’s 1998 novella The Hedge Knight, which is set about a century before the events of Game of Thrones and more than 70 years after the prequel House of the Dragon. It’s a fairly tight and self-contained story, taking place almost entirely at a jousting tournament, which means you don’t need to know much about the series’ long history to jump into the adventures of the poor knight Dunk (Peter Claffey) and his plucky squire Egg (Dexter Sol Ansell).