The Sibyl started a soothsaying cult, the Sibylline Sisterhood, in Pompeii. She lay down the Sibylline Oracles.
The Tenth Doctor stated that she ran the cult less violently than when they tried conquering Earth with the Pyroviles in 79. The Doctor described her as a "hell of a woman" who "could dance the tarantella." He also mentioned she had "nice teeth." It was said he had a brief relationship with Sibyl, but he thought that it wouldn't work, to which she replied, "I know." (TV: The Fires of Pompeii)