[Callas, Maria. (1923–1977)] "Tosca" Program from Final Operatic PerformanceA rare programme for Callas's final operatic performance, a Royal Gala of "Tosca" at the Royal Opera House, Covent Garden, on July 5th, 1965, attended by Queen Elizabeth, the Queen Mother. Callas had originally been scheduled to sing four performances of "Tosca," of which this Royal Gala was to be the last. However, pleading low blood pressure, she cancelled the first three and was replaced by Marie Collier. Callas ended her stage career in the role