Conversation so far:
What is the significance of Antony and Cleopatra?
Price's career climaxed on September 16, 1966, when she sang Cleopatra in Antony and Cleopatra by American composer Samuel Barber and conducted by Thomas Schippers.
Did she work with other well known composers?
CANNOTANSWER.
Are there any other interesting aspects about this article?
Price and Barber had remained close friends and colleagues, and the composer tailored Cleopatra's music to Price's warm middle register and soaring top.
HOw was the performance received?
In the performances, although Price's singing was praised, especially in a powerful death scene, the opera as a whole was widely considered a failure.

Question: Why was it a failure?
Self-contained rewrite: Why was the opera Anthony and Cleopatra a failure?