Battle of the Blackwater

Stannis was among the first on Robert's small council to suspect the truth about the queen's children: that they were born of incest between Cersei and her twin brother Jaime. He told Jon Arryn, the Hand, hoping he would convince Robert. Arryn died soon after, in circumstances that struck Stannis as wrong, and he fled to Dragonstone, gathered what strength his vassals could give him, and hired pirates from the Free Cities to build a fleet the island alone could never have supported.

When Robert died, Stannis sent letters across the realm claiming the crown as the eldest surviving brother and naming Joffrey a bastard. Almost nobody listened. His younger brother Renly had already moved first, in a different direction: he fled to Highgarden, crowned himself, and married Margaery Tyrell to bring the whole Reach behind him. What truly enraged Stannis was that the Stormlands, the Baratheons' own land, sided with Renly too.

Stannis laid siege to Storm's End, held by Ser Cortnay Penrose, but when Renly returned with his army to lift the siege, the numbers turned against him. The battle never happened: a shadow summoned by the red priestess Melisandre killed Renly inside his own tent. Most of his knights then bent the knee to Stannis, though almost a quarter of his forces chose to flee with Ser Loras Tyrell to Bitterbridge, where the widowed queen Margaery waited with a far larger army.

As acting Hand of the King, Tyrion had spent weeks readying the city: he doubled the gold cloaks, burned the shantytowns built up against the walls so they couldn't be used as cover or a ladder, and had a great chain raised that could seal off the whole Blackwater. He also stockpiled every drop of wildfire he could find and sent the mountain clans into the Kingswood to cut off Stannis's supplies by land.

Bad weather and the treacherous waters of the bay slowed Stannis's fleet; he lost a dozen ships along the way, and his men on land spent days harried by those same clans. As he neared the capital, Stannis put Ser Imry Florent in command of the fleet. Imry sent no scouts ahead and attacked at once, certain the small royal fleet stood no chance against his numbers. He left only a handful of mercenary galleys under Salladhor Saan as a rear guard outside the bay.

The royal fleet destroyed the attackers' first two lines; the rest began putting troops ashore. That was when the wildfire hidden aboard the decoy ships caught fire. It spread from hull to hull, trapping both fleets as they tried to retreat and fouling them against the great chain strung between the two towers at the river mouth. Nearly all of Stannis's fleet was destroyed; only eight ships managed to land men on the north bank, and some forty galleys stayed outside the bay. Out of the wreckage jammed against the chain rose an unstable, burning bridge — but a bridge nonetheless.

King's Landing had only about seven thousand gold cloaks to defend it, along with a few hundred mercenaries and knights from the court. Command fell to Tyrion. When Stannis's infantry began crossing the makeshift bridge of wreckage, Tyrion sent Sandor Clegane and Ser Balon Swann to hold them at the landing point; they managed it, but at a heavy cost. With the battlefield burning around them, Clegane refused to lead another sortie, and that refusal nearly broke the defenders' will to keep fighting.

Tyrion led the next sortie himself. Shamed that a dwarf dared what they had not, the defenders returned to the riverbank, scattered the attackers, and retook the Mud Gate. Fighting from a platform of boats that threatened to collapse under him, Tyrion was struck down and gravely wounded by a Kingsguard sword, Ser Mandon Moore — the very man meant to be guarding him.

With the Hand out of the fight, the defenders fell back behind the walls, letting Stannis land still more men. Queen Cersei, fearing for Joffrey, had her son brought back to the Red Keep; the moment the city saw its king withdraw, morale collapsed. Hundreds fled, killing their own officers along the way, among them Ser Jacelyn Bywater. For a while, it looked like Stannis had won.

No one on the battlefield knew it yet, but the Lannisters and the Tyrells had struck an alliance, and Renly's old army had marched from Bitterbridge to join Lord Tywin's. Among the commanders riding in with Tywin was Lord Randyll Tarly, leading the center of an enormous host. The mountain clans Tyrion had sent out before the battle had spent it killing Stannis's scouts and outriders, so he never saw the attack coming.

Tywin's vanguard, led by Ser Garlan Tyrell wearing Renly's own ornate armor, sowed panic through Stannis's ranks, who took him for Renly returned from the dead. Divided, surprised, and badly outnumbered, Stannis's forces broke apart; many lesser lords switched sides in the middle of the fighting, no more loyal to Stannis than they had been to Renly before him. The man known as the Bastard of Nightsong covered the retreat of several thousand men, mostly Florents, who made it to the Lysene galleys waiting outside the bay while the fleet burned.

Stannis survived, but the battle broke House Baratheon of Dragonstone as a fighting force: his fleet was reduced to Salladhor Saan's pirate galleys, and most of the few thousand men who escaped were later left ashore for having thrown down their spears during the rout. With the Tyrells now allied to them, the Lannisters took control of the south and west of the Seven Kingdoms.

Afterward Joffrey handed out titles and honors to those who had saved the city: Tywin was proclaimed Savior of the City, Mace Tyrell and Lord Paxter Redwyne were given seats on the small council, Loras Tyrell was made a member of the Kingsguard, and Garlan Tyrell received House Florent's lands, Brightwater Keep among them, in exchange for his sister Margaery marrying the king. Lancel Lannister was granted Darry, and Petyr Baelish received Harrenhal along with the title of Lord Paramount of the Trident. Bronn, until then captain of Tyrion's guard, was knighted as Ser Bronn of the Blackwater.