When HBO’s Game of Thrones finished its sixth season in 2016, the showrunners, David Benioff and D.B. Weiss were suddenly facing the problem that had always been in the back of the minds of fans. The road so far had been smooth, as the writers on the show had been able to follow the source material from the book series, A Song of Ice and Fire, by George RR Martin. They had done so expertly until that point - and faithfully, and the show had been a remarkable success.
Source：https://www.cbr.com/game-of-thrones-adaptation-10-years-too-early/
