Rosmira, still in disguise as "Eurimene", tells Queen Partenope that "he" challenged Arsace to a duel because "he" was sent by Princess Rosmira to avenge her honour on the man who promised to marry her but jilted her at the altar. The horrified Partenope asks Arsace if this is true and he has to admit it is. Partenope declares she will have nothing more to do with him; Armindo is looking better and better to her as prospective husband.
