A Song of Ice and Fire takes place in a fictional world in which seasons last for years and end unpredictably. Nearly three centuries before the events of the first novel, the Seven Kingdoms of Westeros were united under the Targaryen dynasty, establishing military supremacy through their control of dragons.Their dynasty eventually ended with a rebellion led by Lord Robert Baratheon, in which Aerys "the Mad King" Targaryen was killed and Robert proclaimed king of the Seven Kingdoms. At the beginning of A Game of Thrones, 15 years have passed since Robert's rebellion, with a nine-year-long summer coming to an end.