In Greek mythology Cassandra was the daughter of King Priam and Queen Hecuba of Troy. Her beauty was so great that Apollo granted her the gift of truth. Whenever she spoke it was always truth, sometimes it hurt, sometimes it did not want to be heard but it was always the truth.
When Cassandra did not return his love, Apollo regretting his gift, placed a curse on everyone else, so that no one would ever believe her. She spoke truth but no one listened. Cassandra foresaw the destruction of Troy but was unable to do anything to forestall this tragedy since they did not believe her.