A fifth 'Game of Thrones' prequel in works

"Game of Thrones" universe is expanding to include a previously unannounced fifth prequel.
"Thrones" co-executive producer Bryan Cogman is penning a drama series follow-up to the fantasy drama, writer George RR Martin confirmed on his blog.
The author said now that the deal was signed, he was free to reveal that they have planned not four but five successor shows.
"Truth be told, we've had five scripts in various stages of development for months," Martin wrote.
He, however, had a rider, saying not all the five prequels will make it to the final stage anytime soon.
"You should not expect to see all five shows, though, at least not immediately.. much as I might love the idea, HBO is not about to become the GAME OF THRONES network.

"... But we could possibly see two or even three make it to the pilot stage, with one series emerging on air in 2019 or 2020... And the others maybe later, if they come out as well as we all hope," Martin teased.

Cogman, who has been with the show even before its beginning and has written many of its episodes, will write the prequel and work closely with Martin.
He was first hired as assistant to showrunners David Benioff and D B Weiss even before the pilot was filmed and graduated to being a staff writer, story editor and producer.

Cogman is the best bet after Benioff and Weiss due to his vast experience with the world of Westeros as he has written the maximum episodes of "Game of Thrones" after the showrunners.
"If D&D (showrunners) have been the kings of Westeros for these past seven seasons, Bryan Cogman has surely been the Prince of Dragonstone," Martin wrote.
Jane Goldman, Brian Helgeland, Max Borenstein, and Carly Wray are behind the other four successor shows.
Benioff and Weiss have declined to be involved with the prequels.