<P> Cersei learns that her husband Robert is in danger of finding out that the children he sees as his heirs to the throne are not his . Robert meets his end as the result of a boar attack on a hunting trip, before Ned Stark tells him of the truth about his children . Cersei works quickly to instate her oldest son, Joffrey, on the throne, with her as his chief political advisor and Queen Regent . Joffrey quits listening to his mother . </P> <P> Tywin decides that Cersei does not exercise enough control over her son, and sends Tyrion as an additional political advisor . Cersei and Tyrion do not get along, and constantly try to undermine each other's authority over the crown . As of the end of season 2, Tyrion has accumulated more sway over the Iron Throne, and has shipped Cersei's only daughter off against Cersei's will to be married to the prince of Dorne . </P> <P> Cersei comes to fear that Margaery intends to usurp her as queen, and unsuccessfully tries to alienate Joffrey from her . Cersei is delighted when Tywin learns of the Tyrells' plan to wed Sansa Stark to Margaery's brother Loras and he intervenes to have Tyrion marry Sansa instead, but is furious when Tywin also orders her to marry Loras . When Jaime returns to King's Landing, he immediately seeks out Cersei, who is shocked to discover that his sword hand has been cut off . </P> <P> Cersei has Tyrion arrested after Joffrey is fatally poisoned . It is implied that she knows Tyrion's guilt is highly unlikely, but just wants to see him dead, though Jaime refuses to carry out the order . Indeed, at Tyrion's trial, it is obvious that Cersei has manipulated the entire procedure so that the witnesses give either incomplete or entirely false testimonies to implicate Tyrion and Sansa further in the murder . When Tyrion demands a trial by combat, Cersei quickly chooses Ser Gregor "The Mountain" Clegane as her champion to diminish Tyrion's chances of acquittal, and has Bronn betrothed to a noblewoman so that Tyrion cannot choose him as his champion . Cersei's wish comes true when Tyrion's champion, Oberyn Martell, is killed by Clegane, but she still refuses to marry Loras, even threatening her father with revealing the truth about her relationship with Jaime and the parentage of her children . Tywin rebuffs her threats, though he himself is killed by an escaping Tyrion soon afterwards . </P>

When does cersei lannister die in game of thrones