The “Thrones” team, David Benioff and D.B. Weiss, will be showrunners on the series and collaborate with Nichelle Tramble Spellman (“The Good Wife,” “Justified”) and Malcolm Spellman (“Empire”), who will be executive producers and writers.

“We have discussed ‘Confederate’ for years, originally as a concept for a feature film,” Mr. Benioff and Mr. Weiss said in a statement.

“But our experience on ‘Thrones’ has convinced us that no one provides a bigger, better storytelling canvas than HBO,” they said. “There won’t be dragons or White Walkers in this series, but we are creating a world, and we couldn’t imagine better partners in world-building than Nichelle and Malcolm, who have impressed us for a long time with their wit, their imagination and their Scrabble-playing skills.”

The reaction on social media was less than friendly, with some questioning the need for a show that would depict institutionalized slavery and whether it would glorify the Confederate cause. “Game of Thrones” has come under its share of criticism for its depiction and graphic scenes of rape and slavery, even while it is one of the most popular shows on television.