A domestic scene between Volumnia (Caius Martius' mother) and Vergilia (Caius Martius' wife). They are brought news that Caius is besieging Corioli with Titus Lartius.
Plutarch tells us that Coriolanus was devoted to his mother and that pleasing her was one of his primary motives in achieving success. Shakespeare shows us this from Volumnia's point of view. See the North translation,section 4
At the siege the Volces make a sortie and the Romans are beaten back. Martius repels the Volcian sortie and chases them back into the city.
Shakespeare has Martius chase the Volsces into Corioles by himself, but Plutarch does have a few Romans follow him. See the North translation, section 8
Martius shows his disdain for the soldiers who are more interested in looting than fighting. Despite his wounds, Martius goes off to help Cominius against Aufidius who is bringing up troops to relieve the city. Martius finds Cominius and his men in retreat. Seeing the small number of men with Martius, Cominius assumes that the sortie from Corioles has successfully repulsed the Romans until Martius tells him that the city has in fact been captured. Martius insists on fighting against the Antiates (the people of Antium), the best and strongest Volsces forces, where he knows Aufidius will be fighting. He gives the Romans new hope.
In Plutarch's account Martius reaches Cominius and his men before their battle against the relief force even begins. Aufidius is not mentioned in connection with this battle. See the North translation, section 9
Titus Lartius prepares to leave Corioles to help Cominius and his men. A duel between Martius and Aufidius.
Neither scene is in Plutarch.
The battle is over. Martius refuses to accept a tenth share of the booty, as being a worthy reward only for a mercenary rather than a patriot. He does however accept a horse and freedom for a Coriolan who had once given him hospitality, but whose name Martius cannot remember. Cominius bestows the name Coriolanus on Martius.
Plutarch does not mention Coriolanus' former host's name, but does not say Coriolanus cannot remember it. See the North translation, section 10 and section 11
Aufidius' rage at having been beaten by Coriolanus again.
