Valar morghulis to the first Game of Thrones spin-off series. HBO has decided not to go forward with the would-be prequel series, which was set to take fans well into the past, long before the events of the original HBO epic.

Deadline first reported the news on Tuesday, revealing that showrunner Jane Goldman had informed the cast and crew who worked on the pilot earlier this year that the series will not get a pickup by HBO. On Friday, HBO confirmed the report in a statement to Deadline, saying, "After careful consideration, we have decided not to move forward to series with the Untitled Game of Thrones prequel. We thank Jane Goldman, S.J. Clarkson, and the talented cast and crew for all of their hard work and dedication."

Game of Thrones Creators Won't Be Making a Star Wars Trilogy After All

The prequel series would have centered on a dark era in the history of Westeros. The official logline for the series read, "It chronicles the world's descent from the golden Age of Heroes into its darkest hour. And only one thing is for sure: from the horrifying secrets of Westeros' history to the true origin of the White Walkers, the mysteries of the East to the Starks of legend... it's not the story we think we know."

The pilot was headlined by Naomi Watts and also featured Josh Whitehouse, Miranda Richardson, Naomi Ackie, Denise Gough, Jamie Campbell Bower, Sheila Atim, Toby Regbo, Alex Sharp, Georgie Henley, Ivanno Jeremiah, Marquis Rodriguez, John Simm, Richard McCabe, John Heffernan, and Dixie Egerickx among the cast.

The second potential Game of Thrones spin-off, based on George R.R. Martin's novel Fire & Blood, which reveals the history of House Targaryen, was ordered to series by HBO Max earlier this week.

Game of Thrones is available to stream on HBO.

PHOTOS: The Ultimate Game of Thrones Holiday Gift Guide

Emilia Clarke and Kit Harington, <em>Game of Thrones</em>Emilia Clarke and Kit Harington, Game of Thrones