At the beginning of the first novel "A Game of Thrones", Stannis comes to suspect that Robert's children with Cersei Lannister are not actually his. He suspects that Robert will not believe his word alone, so he reveals his suspicions to Robert's Hand of the King and trusted friend, Lord Jon Arryn. The two discover several of Robert's bastard children in King's Landing and begin to gather proof of the bastardy of Cersei's children. Jon Arryn agrees to foster his young son and heir, Robert Arryn, at Dragonstone. However, Jon Arryn dies unexpectedly. Stannis suspects that the Lannisters assassinated Jon Arryn, so he immediately leaves the capital for Dragonstone.