In 1941, Callas made her professional debut with the Royal Opera of Athens in a modest role in Franz von Suppé's Boccaccio. Later in the year, she took on her first major role in Tosca.
During World War II, Callas struggled to find roles. In the mid-1940s, she moved back to New York to spend time with her father and look for work, but experienced a number of rejections. She eventually moved to Verona, where she met rich industrialist Giovanni Meneghini. The two married n 1949.
Callas's Italian opera debut took place at the Verona Arena in August 1947, in a performance of La Gioconda. Over the next few years, under the management of her husband, Callas continued to perform in Florence and Verona to critical acclaim. Though her voice captivated audiences, as her fame increased, Callas developed a reputation as a temperamental, demanding diva and was nicknamed "The Tigress." Fiercely resilient, Callas said of audience members' jeers, "Hissing from the gallery is part of the scene. It is a hazard of the battlefield. Opera is a battlefield, and it must be accepted."
In 1954, Callas made her American debut in Norma at the Lyric Opera of Chicago. The performance was a triumph and was seen as a signature role. In 1956, she at last had the opportunity to sing with the Metropolitan Opera in her home city of New York, but in 1958 was fired by director Rudolf Bing. Callas's marriage had also begun to unravel. Callas and Meneghini split at the end of the decade, during which time she was having an affair with shipping magnate Aristotle Onassis. (He would later wed former U.S. first lady Jacqueline Kennedy, causing much sadness for Callas, with Onassis nonetheless still trying to woo the singer after his nuptials.)
During the 1960s, Maria Callas's formerly stellar singing voice was discernibly faltering. Her performances grew fewer and farther between, as a result of her frequent cancellations. Though she formally retired from the stage in the early '60s, Callas made a brief return to performing with the Metropolitan Opera mid-decade. Her final operatic performance was in Tosca at Covent Garden in London on July 5, 1965, attended by Queen Mother Elizabeth. In 1969, she also appeared in the title role of the film Medea.
In the early 1970s, Callas tried her hand at teaching. In '71 and '72, she conducted master classes at Juilliard in New York.
