The Siege of Pyke was the final battle of the Greyjoy Rebellion, taking place approximately nine years before the beginning of the Game of Thrones series. The castle of Pyke on the Iron Islands, the stronghold of House Greyjoy, was taken by forces loyal to King Robert Baratheon in an assault after a siege.
The Iron Islands were outnumbered ten to one. During the final assault on Pyke, a battle-crazed warrior priest of the Lord of Light named Thoros of Myr led the way through a breach in the wall with his flaming sword, Jorah Mormont of Bear Island not far behind him. Eddard Stark and Jaime Lannister were also key fighters for the Iron Throne during the battle. Balon's second son and heir after Rodrik Greyjoy's death, Maron Greyjoy, was killed in the fighting at Pyke. Maron's death was due to a collapsing tower during the battle.
The rebellion was crushed and Balon was forced to surrender. He was accepted back into the king's peace, but only on the condition that his last surviving son Theon be made a ward of House Stark as hostage for his good behavior. Theon was just 8 years old at the time. Robert's victory cemented his hold on the throne, after having overthrown the Targaryens a few years before. King Robert knighted Jorah Mormont for his valor in the battle.
In the books
In the A Song of Ice and Fire novels, the Siege of Pyke similarly took place at the end of the Greyjoy Rebellion. Despite early successes - such as burning the Lannister fleet at anchor - the Greyjoys were defeated at sea by Stannis Baratheon's fleet and forced to retire to Pyke. The forces loyal to King Robert Baratheon breached the walls with siege ships and charged through the breach. Once it was clear that the battle was lost, Balon Greyjoy surrendered and bent the knee in fealty to King Robert once more.