Robert's Rebellion was a civil war in the fictional land of Westeros, occurring about 17 years before the events of A Game of Thrones. It was sparked by the kidnapping of Lyanna Stark by Prince Rhaegar Targaryen, which led to a coalition of noble houses, including House Stark and House Baratheon, rising against the ruling Targaryen dynasty. The rebellion culminated in the fall of King Aerys II Targaryen, also known as the Mad King, and the establishment of Robert Baratheon as the new king. This conflict significantly altered the political landscape of Westeros and set the stage for future events in the series.