Birgit Nilsson, who has died aged 87, was the leading Wagnerian soprano of her day and, in the opinion of many critics, her performances bore comparison with those of Kirsten Flagstad and Frida Leider.
Birgit Nilsson had a rich, powerful voice.
In physical appearance, she was less monumental than her predecessors - a small, compact, dark woman - but she had a theatrical presence and a voice of heroic fire and grandeur.
Birgit Nilsson was born in southern Sweden, the daughter of a farmer. She was 19 before she overcame parental opposition to a musical career and entered the Stockholm Royal Academy of Music.
In 1946, she appeared with the Stockholm Opera as Agathe in Der Freischutz, with only three days notice, and in the following year as Lady Macbeth in Verdi's opera.
Her first important engagement outside Sweden was at Glyndebourne in 1951 as Electra in Mozart's Idomeneo.
During the next few years, she began to specialise in Wagnerian roles. But her pre-eminence in this field was not finally established until 1957 when she sang the part of Isolde at Bayreuth and made her London debut as Brunnhilde in the complete "ring" cycle at Covent Garden.
Her stardom was confirmed when she played Isolde again at the New York Metropolitan Opera in 1959.
She once said, though, that the single biggest event in her life was when she was asked to perform at the opening of the 370th season at Milan's La ScalaI as Turandot in 1958.
Performing in Elektra in 1967
She was beieved to have been one of the two or three most highly-paid opera singers in the world.
In 1966, at the New York Met, she was asked to sing the parts of both Venus and Elisabeth in Tannhauser. In 1969, the Austrian government gave her the honorary title of Kammersangerin (court singer).
In September 1970 Birgit Nilsson gave her first song recital in Britain at the Royal Festival Hall in celebration of the birth of her compatriot, Jenny Lind, "the Swedish nightingale".
Six years later she celebrated 30 years in opera by singing her favourite role, Isolde, at the Royal Theatre, Stockholm.
She retired in 1984.