"For me, to sing is to speak singing," he famously remarked when asked about his exquisite diction.
The Trieste-born singer made his debut in 1957 at the Teatro Nuovo di Milano, and sang on the world's great stages, including the Metropolitan Opera House, where he made his debut in 1969, and La Scala, where he sang many times. He retired from performing in 1992 after a serious car accident; after his retirement, he dedicated himself to teaching.