The first Game of Thrones prequel is reportedly dead. Created by Jane Goldman (Kingsman: The Secret Service) and A Song of Ice and Fire author George R.R. Martin, and starring Naomi Watts (King Kong) in the lead, the untitled Thrones prequel spin-off series — sometimes referred to as The Long Night / Bloodmoon — was set thousands of years prior to events of the main series and would have “chronicled the world's descent from the golden Age of Heroes into its darkest hour.” It was greenlit in June last year and wrapped up filming on the pilot earlier this year, but HBO has decided to not move forward with it.
Deadline first brought word on the first Game of Thrones prequel being cancelled, claiming that co-creator, showrunner, and writer Goldman had emailed the cast and crew of the series to inform them as much. Variety confirmed the development from its own sources shortly after. HBO has declined to comment, though the fact that the series wasn't given a mention at its parent company WarnerMedia's HBO Max presentation — the upcoming streaming service set to launch in May 2020 in the US — while a new Game of Thrones prequel series called House of the Dragon, based on Fire & Blood, was announced, all but confirms it.
If you're wondering why HBO has decided to drop the first Thrones prequel, the answer isn't clear though it has naturally had something to do with the quality of the pilot. Deadline notes that there were rumours about production issues in Northern Ireland, and it underwent re-editing during a lengthy post-production after weak feedback to a first cut. It's also possible that HBO wasn't convinced that a Thrones prequel with little to no connection to the main series, owing to its thousands-of-years-ago setting, would be able to hold fans, though that's simply speculation on our behalf.
For what it's worth, Game of Thrones itself produced an infamous disastrous pilot episode, which was thrown out to start over from scratch. It remains to be seen if HBO will give the first prequel another go. Until then, we have the second prequel, House of the Dragon, to talk about, which is moving forward with a straight-to-series order.