Bing later said that Callas was the most difficult artist he ever worked with, "because she was so much more intelligent. Other artists, you could get around. But Callas you could not get around. She knew "exactly" what she wanted, and "why" she wanted it." Despite this, Bing's admiration for Callas never wavered, and in September 1959, he sneaked into La Scala in order to listen to Callas record "La Gioconda" for EMI. Callas and Bing reconciled in the mid 1960s, and Callas returned to the Met for two performances of "Tosca" with her friend Tito Gobbi.