"some trembling Kassandra gibbering prophecies"

 In Ancient Greek myth, Kassandra (or Cassandra) was the daughter of King Priam of Troy, who was given the gift of prophecy by Apollo. However when she did not return Apollo's love for her he cursed her so that no one would believe her prophecies.

Cassandra appears in many Greek sources, including Homer's Iliad, Aeschylus' Agamemnon and Euripedes' Trojan Women and Electra.