Christoff was born in Plovdiv on 18 May 1914. Educated as a lawyer, he was heard by the King of Bulgaria while singing with the famous Gusla Choir and at the behest of the King in 1942 he was granted a scholarship to study singing. He moved to Rome and for several years his teacher there was the baritone Riccardo Stracciari. He made his operatic debut in 1946 as Colline in La bohème in Reggio di Calabria, where his singing of the Coat Song in the last act earned two encores.

Although not a particularly large man, Christoff’s magnetic stage presence and piercing eyes made him always the centre of attention on stage, and he exerted command and authority not only over his fellow performers but on the audience as well. His rich, sonorous voice was compact and perfectly focused and, like his physical presence, made its effect in every part of the theatre. His performances as Tsar Boris were not declamatory in the normal sense, but their intensity drew everyone in his audience right down to him on the stage. Every word was clear, every gesture meaningful and every note unforgettable. One might also say that the dark, resonant timbre of his voice was unmistakable and that the sheer emotional intensity of his performances has never been surpassed.

Christoff’s perfectly controlled Slavic voice was ideally suited to the Russian repertoire, especially the roles particularly associated with Chaliapin. He was also ideal for a number of Verdi bass parts, notably Philip II (Don Carlo), Padre Guardiano (La forza del destino), Procida (I vespri siciliani) and Fiesco (Simon Boccanegra), but his repertoire covered a wide range of other Italian roles and a few French ones as well, particularly Mephistopheles in Gounod’s Faust. His German roles included Rocco (Fidelio), King Mark (Tristan und Isolde), Hagen (Götterdämmerung) and Gurnemanz (Parsifal). His concert repertoire also ranged widely, taking in the main composers of the Russian Romantic era, and this survey of Christoff’s art on record begins with what the writer John Steane remarked ‘may well constitute his prime contribution to recorded music and his supreme claim upon the enduring gratitude of musicians at large’, namely the complete songs of Mussorgsky. When first released on LP in 1958, the set was a milestone.

On Discs 4–8 of this set Christoff surveys the remainder of Russian art-song with the most intimate fusion of text and music – a power of advocacy unmatched by other singer on record, even the great Chaliapin.

CD 9 covers Christoff’s main Russian stage roles. These are recordings made in London with the Philharmonia Orchestra between 1949 and 1952 when Christoff was still at the beginning of his career, but already a fully developed and mature artist.

The final CD ranges right across Christoff’s operatic repertoire, with arias by Gounod (Faust) and Gluck (Iphigenia in Aulis), as well as Verdi, including the two great scenes from Simon Boccanegra and Don Carlo in which Christoff and Gobbi strike dramatic sparks off each other. In both cases, Christoff portrays with immense dignity and command the elderly figure of authority (Fiesco and King Philip II) and Gobbi is the young firebrand (Simon Boccanegra and Rodrigo, Marquis of Posa) confronting the older man. The remaining tracks return us to Russian opera and some of Christoff’s greatest roles, starting with Ivan Susanin in Glinka’s A Life for the Tsar. Finally, we hear three extracts from the 1962 stereo recording of Boris Godunov conducted by André Cluytens: firstly Boris’s Prayer from the prologue, where he has finally agreed to become Tsar. Later in the opera a chiming clock terrifies him and he begs God’s mercy on his guilty soul, and finally we hear again Boris’s death scene.