Act I. The Greek camp before Troy. It has been deserted by the Greeks.

The people of Troy, rejoicing at what they believe to be the raising of the siege, are bustling about the camp. Many of them, however, are standing amazed about a gigantic wooden horse. There is only one person who does not rejoice, _Cassandra_, _Priam's_ daughter, whose clairvoyant spirit foresees misfortune. But no one believes her dire prophecies, not even her betrothed, _Choroebus_, whom she implores in vain to flee.