Robert Baratheon is the eldest son of Steffon and Cassana Baratheon. He has two younger brothers, Stannis and Renly. His parents were killed when their ship sank off the coast of Storm’s End and Robert was brought up by Jon Arryn. Robert became close friends with Ned Stark who spent time in the house of Jon Arryn.
Robert was betrothed to Ned Stark’s sister Lyanna who was taken by Rhaegar Targaryen. After the Mad King Aerys II killed Lyanna’s father, Rickard, and her brother Brandon, Robert sought revenge. Robert’s Rebellion succeeded in overthrowing the Targaryens and Robert took the Iron Throne and became King of Westeros.
He appointed Jon Arryn Hand of the King and married Cersei Lannister. He has three children, Joffrey, Myrcella, and Tommen but does not know that Jaime Lannister fathered them.
At the beginning of the series, Jon Arryn has been murdered, and Robert has ridden north to Winterfell to persuade Ned Stark to be his Hand of the King. Robert suggests that the two families unite with the marriage of his son Joffrey to Ned’s daughter, Sansa.
Happy to have Ned in King’s Landing, Robert leaves the government to Ned and spends his time drinking, hunting and enjoying women. Robert has 19 bastard children including an infant daughter, Barra and a son Gendry who works as a blacksmith in King’s Landing.
Robert embarks on a hunting expedition and, after drinking too much wine supplied by Cersei’s nephew, Lancel, he is fatally wounded. On his deathbed, he writes a decree that Ned should act as regent for Joffrey before dying of his injuries.