From the Satyricon by Gaius Petronius. Eliot (1971) gives this translation:
The Satyricon tells of the misadventures of a former gladiator through the Roman Empire in the first century A.D. Only fragments of the story still exist. The scene Eliot quotes occurs during a feast at the villa of a wealthy buffoon named Trimalchio.
The Sibyl of Cumae was a prophetess in service to Apollo and a great beauty. Apollo wished to take her as his lover and offered her anything she desired. She asked to live for as many years as there were grains in a handful of dust. Apollo granted her wish, but still she refused to become his lover. In time, the sibyl came to regret her boon as she grew old but did not die. She lived for hundreds of years, each year becoming smaller and frailer, Apollo having given her long life but not eternal youth. When Trimalchio speaks of her in the Satyricon, she is little more than a tourist attraction, tiny, ancient, confined, and longing to die.