he became assistant conductor of the RAI (Italian Radio) Orchestra in Rome, becoming its principal conductor in 1946. Four years later he was involved in the founding of the Milan Radio Orchestra, working with them from 1946 to 1954, as well as with the RAI's Rome orchestra. Giulini and conducting opera Although Giulini conducted La traviata for Italian radio in 1948, he conducted his first staged opera in 1950 in Bergamo. It was La traviata and he returned the following year, this time with Maria Callas and Renata Tebaldi alternating in the role of Violetta. Also, he revived several obscure operas, including works by Alessandro Scarlatti. His work in Bergamo came to the attention of Arturo Toscanini, who asked to meet the young conductor, and the two men formed a deep bond. Toscanini recommended Giulini for the musical directorship at La Scala; Giulini had also won the attention and support of Victor de Sabata, the principal conductor of La Scala, who engaged him as his assistant. Giulini conducted his first opera at La Scala, Falla's La vida breve, in February 1952 and succeeded De Sabata as its music director in 1953 after a heart attack caused the older man to leave the position. In his five years in the position, Giulini conducted 13 productions, which included: Though highly admired, he resigned after members of the audience jeered Maria Callas during a run of operas from 16 February to 27 April 1956. His UK debut took place at the 1955 Edinburgh Festival conducting Verdi's Falstaff for the Glyndebourne Opera company when it toured to that city. In 1958, Giulini conducted a highly acclaimed production of Verdi's Don Carlos at the Royal Opera House, Covent Garden (directed by Visconti), where it was also noted that "what emerged under Giulini's baton was a consistent, convincing masterpiece of astonishing power and lyrical tension." Although he returned to Covent Garden in 1957, it became clear that, after two more Covent Garden performances in 1961 and 1964 (the famous black-and-white Il trovatore) and another at the Holland Festival in 1965, where he disagreed so strongly with the visual treatment of The Marriage of Figaro on the stage that he refused to conduct, and only concert performances were given, Giulini would abandon opera, not wanting to compromise his artistic vision. Almost without exception from then on, he concentrated on orchestral works. As illustrated, his relationships with opera