As Game of Thrones heads slowly to a close, showrunners D.B. Weiss and David Benioff begin to prepare for their new HBO show Confederate amid widespread controversy.

The show is an alternative history where the South has successfully seceded from the Union, meaning that slavery is still legal as America heads towards its third Civil War. The story would attempt to cover both sides of the Mason-Dixon Demilitarized Zone — “freedom fighters, slave hunters, politicians, abolitionists, journalists, the executives of a slave-holding conglomerate and the families of people in their thrall.”

The modern-day reimagining of slavery from two white men who have already been criticized for the lack of diversity in Game of Thrones has caused great concern, culminating in a grassroots Twitter campaign this Sunday for #NoConfederate.

The campaign was started by activist April Reign who tweeted, “We believe the time to speak up is now, before the show has been written or cast.”

We believe the time to speak up is now, before the show has been written or cast. Before @hbo invests too much money into #Confederate.

— April (@ReignOfApril) July 28, 2017

The hashtag trended #1 nationwide and #2 worldwide this Sunday night during Game of Thrones, with thousands taking to Twitter to voice their beliefs that the show would do more harm than good.

The pain of my ancestors shouldnt exist as entertainment for the white gaze. #NoConfederate

— Black Aziz Ansari ? (@Freeyourmindkid) July 31, 2017

Why can't we have show w/ alterverse where Lincoln wasn't assassinated, Reconstruction wasn't ended & Jim Crow never began? #NoConfederate

— Bree Newsome (@BreeNewsome) July 30, 2017

Reign also voiced concern over the track record of Benioff and Weiss in largely ignoring POC in their hit show, saying, "What confidence should we have in two gentleman who can't talk about race on their own show and have had seven seasons to introduce significant characters of color?"

Regarding these criticisms, D.B. Weiss stated, "We know that the elements in play in a show like Confederate are much more raw, much more real, and people come into them much more sensitive and more invested, than they do with a story about a place called Westeros….they need to be dealt with in very, very different ways. And we plan, all of us I think, to approach Confederate in a much different spirit, by necessity."

HBO and the show creators also defended the controversial subject matter. "It goes without saying slavery is the worst thing that ever happened in American history. It’s our original sin as a nation. And history doesn’t disappear. That sin is still with us in many ways," Weiss said. "Confederate, in all of our minds, will be an alternative history show. It’s a science-fiction show. One of the strengths of science fiction is that it can show us how this history is still with us in a way no strictly realistic drama ever could, whether it were a historical drama or a contemporary drama. It’s an ugly and a painful history, but we all think this is a reason to talk about it, not a reason to run from it."

The premiere cable company and the show’s writing team (which also includes husband and wife duo Malcom Spellman and Nichelle Tramble Spellman) plan to continue with the show and urge people to “reserve judgment until there is something to see." Benioff commented on the initial outrage, saying, “It’s just a little premature. You know, we might fuck it up. But we haven’t yet.”

But as Richard Newby, executive editor of the film criticism site Audiences Everywhere, pointed out to The Hollywood Reporter, "When slavery becomes the dominant image of a people in pop culture, that's what black people become associated with. I don't think that's beneficial to anyone to continue to suggest that this is the only kind of story where our lives matter."

Because, for some, the Confederacy isn't alt-history. It's right now. #NoConfederate @hbo pic.twitter.com/NEm2vmghEJ

— April (@ReignOfApril) July 31, 2017

Right now, the contentious venture is set to start in 2019 after Game of Thrones comes to an official end, but based on Sunday’s Twitter takeover, HBO might want to take that time to think over the consequences of Confederate.