Although there were some substantial alterations from what readers may be familiar with from George R. R. Martin's Fire & Blood, the first episode of House of the Dragon debuted to widespread critical praise.
As something of a prologue to Martin's A Song of Ice and Fire series, Fire & Blood was published in 2018. From Aegon the Conqueror's conquest and the creation of the Seven Kingdoms through the Dance of Dragons and the start of Targaryen rule's demise, the book narrates the history of the Targaryen family in Westeros.
Only a few months after Fire & Blood's publication, in 2018, George R. R. Martin hinted at the possibility of a Game of Thrones spinoff based on the book. Martin served as co-creator and executive producer of House of the Dragon, which was ordered straight to series on HBO a year after it was first announced by showrunners Ryan Condal and Miguel Sapochnik.