Marcellus has Demetrius released and orders him to go on his own to the Gallio home. Marcellus is surprised to find Demetrius waiting for him when he arrives. Unofficially, Marcellus had freed Demetrius, but Demetrius feels honor bound to compensate Marcellus by being his servant. Demetrius accompanies Marcellus to Judea but, before the galley sails, Diana comes to see Marcellus, pledging her love for him and her intention to intercede on his behalf with Tiberius. Marcellus declares his love for Diana and asks her to make the emperor promise not to give her in marriage to Caligula.