The chorus of Egyptian citizens, Roman attendants, and soldiers of both nations, raise their voices in triumph, welcoming their new leader Giulio Cesare (Julius Caesar) after his victorious defeat of Pompeo (Pompey) at Pharsalus (‘Viva il nostre Alcide’). Cesare offers them a grand address, claiming the land of Egypt under Roman rule (Aria ‘Presti omai’), but the reality of war is not that simple. Cesare confides in Curio, who is a Roman tribune (or officer), that although defeated, Pompeo still lives, and he is calling on Tolomeo (Ptolemy), the King of Egypt, to send him reinforcements.
At that moment, Pompeo’s wife and son approach Cesare. Cornelia pleads with him to spare her husband’s life. Cesare is already victorious, he should lay down his arms and make peace with Pompeo. Cesare agrees; he will pardon Pompeo and accept his friendship.
Tolomeo’s general, Achilla, arrives, flanked by Egyptians carrying golden basins. He brings gifts from Tolomeo, and an invitation for