Before Ned Stark lost his head and King Robert was killed by a boar, the world of Game of Thrones enjoyed a time of relative peace and prosperity. The Great Houses were aligned, the Starks were proud members of the Seven Kingdoms, and the Night's Watch still manned a standing Wall. There were some fleeting battles, including the Greyjoy Rebellion, but they largely experienced a peace that Westeros has seldom known. It was a period of calm that came in the wake of a bloody and painful war: Robert's Rebellion.
Source：https://www.cbr.com/game-of-thrones-roberts-rebellion-explained/
