The Blackwater Rush, before the gates of King's Landing.
Who fought
Stannis Baratheon's fleet and army against the Lannister-Tyrell defense of King's Landing
Outcome
Stannis Baratheon's assault on King's Landing was broken by Tyrion Lannister's wildfire trap and a timely Lannister-Tyrell relief force; the city held, and Stannis's bid for the throne never recovered.
The most storied siege of the war ended in a single night, when the river itself turned to fire and a relief force nobody in the city had been told to expect arrived just in time.
Commanders
Stannis Baratheon
Tyrion Lannister (defense)
Tywin Lannister and Mace Tyrell (relief)
What happened
Of the great battles fought over King's Landing, none looms larger in the popular telling than the fight for the city upon the Blackwater Rush. Stannis Baratheon, the dead king's brother and the sternest claimant to the crown, brought a great fleet up the river to take the capital from the boy Joffrey; the city seemed lost within a night. Then the river itself caught fire, a relief force fell on the attackers from behind, and Stannis's cause was broken before the sun rose again.
The particulars of exactly how the city survived — the trap that was laid, the men who laid it, and the debts of gratitude the crown chose not to pay — belong to the deeper record, and the chronicle holds them back here for readers who have not yet reached that part of the tale.
The Battle of the Blackwater in the novels
This carries how the battle plays out in the published novels. Read on only if you do not fear to know.
Stannis Baratheon brought the largest fleet the narrow sea had seen in living memory up the Blackwater Rush to take King's Landing while the city's regent, Tyrion Lannister, had a fraction of the men and none of the reputation to hold it. Tyrion answered with wildfire: a single ship, crewed only by a condemned man, was sent drifting into the packed enemy fleet before a fire arrow set the river itself alight. Whole squadrons burned at their oars in green flame that the smallfolk, watching from the walls, took for the end of the world.
It was not enough on its own — a burning fleet can still put men ashore — so Tyrion had ordered a second trap prepared in secret: a massive chain strung across the river's mouth beneath the waterline, raised only after Stannis's ships had sailed well past it. Those that escaped the fire found the sea behind them sealed and the city's defenders, Tyrion among them, waiting on the beach for whatever came ashore.
Even so, Stannis's numbers began to tell, and the city was on the edge of falling when a Lannister-Tyrell relief force under Tywin Lannister and Mace Tyrell arrived at the defenders' backs, having marched in secret and in time. Stannis's army broke and fled; his ambitions for the Iron Throne never recovered the momentum this single night cost him. The city was saved, though the man who saved it — badly burned and half-forgotten in the celebrations that followed — would spend a long while resenting exactly how little thanks his family gave him for it.
These partings name deaths, endings, and roads not yet ridden in the books. Unveil them only if both roads are known to you — or if you do not fear to know.
In the timeline
SourcesACOK · TyrionACOK · DavosACOK · Sansa
Explore further
Commanders
Houses in the field
Elsewhere in this war
What was The Battle of the Blackwater?
The most storied siege of the war ended in a single night, when the river itself turned to fire and a relief force nobody in the city had been told to expect arrived just in time.
Is The Battle of the Blackwater from the books or the show?
Book canon. This entry follows George R. R. Martin's novels and histories, and notes where the television series diverges rather than following it.