A stretch of grassland in the Reach that took its grim new name from the battle itself.
Who fought
The Blackfyre pretenders under Daemon I Blackfyre against the loyalist army of King Daeron II Targaryen
Outcome
Daemon I Blackfyre and two of his sons were slain; the rebellion collapsed, though its survivors fled into exile to found the Golden Company and trouble the Iron Throne for two more generations.
The bastard-born pretender who claimed the Iron Throne by right of a stolen sword died on a field that saw more dead than any battle since the dragons burned the Reach — and the crown he sought passed to no one at all.
Commanders
Daemon I Blackfyre, with his sons Aegon and Aemon Blackfyre and his half-brother Aegor ‘Bittersteel’ Rivers
King Daeron II Targaryen, with Prince Baelor Breakspear and Ser Brynden ‘Bloodraven’ Rivers
What happened
Daemon Blackfyre had the look of a king, the valor of a champion, and — thanks to a dying Aegon IV's deathbed gift of the ancestral sword Blackfyre — a claim that half the realm found more convincing than his trueborn half-brother's. When he raised his rebellion in 196 AC, great lords flocked to his black dragon banner, and the loyalist host that marched to meet him was, by every honest account, in for the fight of its life.
The two armies met in the Reach, and the slaughter that followed was reckoned the worst the Seven Kingdoms had seen since the Field of Fire itself. Daemon Blackfyre and two of his young sons, both bearing swords forged to look like Blackfyre so no man could say which pretender was the true one, were cut down together by the arrows of Ser Brynden Rivers — Bloodraven, the king's own bastard half-brother and no friend to bastards who reached for crowns not theirs. The rebel host broke apart soon after.
Daeron II kept his throne, but the victory cost him his stomach for another such day; the maesters note he never again rode to war himself. Aegor Rivers, Daemon's loyal half-brother, gathered what remained of the Blackfyre loyalists and fled across the narrow sea rather than kneel — the seed of the Golden Company, and of three further rebellions still to come.
In the timeline
SourcesF&B · The Blackfyre RebellionTWOIAF · The Targaryen Kings
Explore further
Commanders
Where it was fought
Houses in the field
What was The Redgrass Field?
The bastard-born pretender who claimed the Iron Throne by right of a stolen sword died on a field that saw more dead than any battle since the dragons burned the Reach — and the crown he sought passed to no one at all.
Is The Redgrass Field 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.