Sack of King's Landing

The Sack of King's Landing was the battle that ended Robert's Rebellion and consisted of a devastating assault on the city of King's Landing by the army of House Lannister. During the battle, the Mad King was slain along with most of his loyal retainers and those family members who had not fled to the island of Dragonstone.

Lord Tywin Lannister was the architect of the victory and commanded the assault as a way of proving his loyalty to Robert Baratheon after deciding to join the war very late in the day.

Cripples, Bastards and Broken Things
The singer Marillion offers to sing Tyrion Lannister a song about his father's victory at King's Landing, the thought of which turns Tyrion's stomach.

In the books
In the Song of Ice and Fire novels, the Sack of King's Landing is described as a particularly brutal and treacherous battle. During Robert's Rebellion, the forces of Houses Stark, Baratheon, Arryn and Tully had fought against those houses owing direct allegiance to House Targaryen, but of the other Great Houses only House Tyrell had sworn themselves to the Mad King's cause, and most of their forces were tied down in the south, besieging the Baratheon stronghold of Storm's End. House Martell of Dorne had reluctantly committed troops to the Targaryen cause only because the Mad King held Princess Elia Martell, the wife of Prince Rhaegar Targaryen, in King's Landing as a virtual hostage. The Martells were insulted by Rhaegar having started the war in the first place by taking Lyanna Stark as a lover, dishonoring his own marriage to Elia.

During the fighting, House Greyjoy refused to take any part and House Lannister similarly sat out the bulk of the war, Lord Tywin having felt insulted by many of the Mad King's own actions in the preceding years. However, after Robert's victory at the Battle of the Trident Tywin rushed his army to King's Landing. In front of the city gates, he proclaimed that the Lannister force had come to defend the city from the rebel army rushing south under Eddard Stark. The city's defenders threw open their gates to the 'reinforcements', only for the Lannister troops to betray the defenders and put them to the sword. The city was brutally sacked, with thousands of smallfolk caught up in the fighting and killed as well as soldiers on both sides.

During the battle, Ser Jaime Lannister killed the Mad King by stabbing him through the back at the foot of the Iron Throne. Knights loyal to his father burst into the throne room to see the end of the incident, insuring that Jaime would forever be known as 'the kingslayer'.

During the closing stages of the battle, Lannister troops scaled Maegor's Holdfast and killed Princess Elia Martell and her two children, Princess Rhaella Targaryen and Prince Aegon. According to rumor, the dread knight Gregor Clegane performed horrible deeds during this event.

The death of the Mad King and his grandchildren saw the end of Robert's Rebellion and allowed Robert Baratheon to claim the Iron Throne, even though the Mad King's son and daughter Viserys and Daenerys had escaped to the Free Cities to live in exile. Due to the death of Princess Elia, Dorne and House Martell withdrew from active involvement in the affairs of the rest of Westeros afterwards.