Her first appearance at Covent Garden was in 1937, as Amneris, and she returned to London a number of times, notably in the role of Adalgisa in partnership with Maria Callas's Norma in 1952 and 1957.
It had sufficient flexibility for her to undertake such roles as Rossini's L'italiana in Algeri, but it was in noble, dramatic parts that she was heard to greatest effect.
By her own account, she was short and plump, and she admitted her shortcomings as an actress, but she achieved dramatic power and characterization through the quality of her voice and technique.
She was highly disciplined in her choice of roles and in the number of appearances she made, refusing to take assignments which she felt were not right for her voice, and this no doubt contributed to the longevity of her career at the highest level.
Stignani recorded a range of operatic arias in the late 1930s and early 1940s reflecting the variety of roles in her repertoire, and these have been variously reissued on CD.