Mezue ahịrịokwu na-esonụ: N'oge ngwụsị afọ 1950 Varviso mere ọtụtụ ma ọ bụ ndị a ma ama na-eduzi ndị ọbịa, gụnyere Deutsche Oper Berlin (1958), Paris Opera (1958), na San Francisco Opera (1959), nke ikpeazụ bụ ọrụ mbụ ya na United States. N'afọ 1958, o duziri ihe nkiri ụwa mbụ nke Heinrich Sutermeister's "" na
Ihe ngosi ụwa nke Brussels. N'abalị iri n'ọnwa Ọktoba n'afọ 1961, ọ laghachiri San Francisco iji duzie emume mbụ nke Britten's "A Midsummer Night's Dream". Ọ duziri "The Marriage of Figaro" maka arụmọrụ mbụ ya na Glyndebourne Festival na 1962 sochiri mmepụta nke "Der Rosenkavalier" maka mmalite ya na Covent Garden n'afọ ahụ. Ọ laghachiri na Royal Opera n'oge niile nke ọrụ ya, na-eduzi ọtụtụ ihe ngosi nke sitere na ọrụ ọkọlọtọ site n'aka Mozart, Puccini, Strauss, na Wagner, na-eme obere opera dị ka Debussy's "Pelléas et Mélisande".