Frederick Sandys, Cassandra, c. 1863–1864. Ulster Museum, Belfast. The story of Cassandra's curse has several versions. The most widespread says that Apollo gave her the gift of prophecy and that, when she rejected him, he cursed her so that no one would believe her. This explains the expression “Cassandra prophecy,” used for a prophecy that will come true but that no one believes when it is uttered. A late version of the ancient tradition, preserved in a commentary on the Aeneid known as Servius auctus or Servius Danielis, adds that after Cassandra rejected him, Apollo hid his anger for a...