Nicolai Ghiaurov (or Nikolai Gjaurov, Nikolay Gyaurov, Bulgarian: Николай Гяуров) (September 13, 1929 – June 2, 2004) was a Bulgarian opera singer and one of the most famous basses of the postwar period. He was admired for his powerful, sumptuous voice, and was particularly associated with roles of Verdi. Ghiaurov married the Italian soprano Mirella Freni in 1978, and the two singers frequently performed together. They lived in Modena up until Ghiaurov's death in 2004 of a heart attack.

Ghiaurov was born in the small mountain town of Velingrad in southern Bulgaria. As a child, he learned to play the violin, piano and clarinet. He began his musical studies at the Bulgarian State Conservatory in 1949 under Prof. Hristo Brambarov. From 1950 until 1955, he studied at the Moscow Conservatory.

Ghiaurov's career was launched in 1955, when he won the Grand Prix at the International Vocal Competition in Paris and the First Prize and a gold medal at the Fifth World Youth Festival in Prague. Ghiaurov made his operatic debut in 1955 as Don Basilio in Rossini's The Barber of Seville in Sofia. He made his Italian operatic debut in 1957 in Teatro Comunale Bologna, before starting an international career with his rendition of Varlaam in the opera Boris Godunov at La Scala in 1959. 1962 marked Ghiaurov's Covent Garden debut as Padre Guardiano in Verdi's "Forza del Destino" as well as his first appearance in Salzburg in Verdi's "Requiem," conducted by Herbert von Karajan.

Luciano Pavarotti, Cavaliere di Gran Croce OMRI (12 October 1935 – 6 September 2007) was an Italian operatic tenor, who also crossed over into popular music, eventually becoming one of the most commercially successful tenors of all time. He made numerous recordings of complete operas and individual arias, and established himself as one of the finest tenors of the 20th century. He was one of The Three Tenors and became well known for his televised concerts and media appearances. Pavarotti was also noted for his charity work on behalf of refugees and the Red Cross, amongst others.

Pavarotti began his professional career as a tenor in 1961 in Italy. That same year, he made his first international appearance in La traviata in Belgrade, Yugoslavia. He sang in opera houses in addition to Italy, in the Netherlands, Vienna, London, Ankara, Budapest and Barcelona. The young tenor earned valuable experience and recognition while touring Australia at the invitation of soprano Joan Sutherland in 1965. He made his United States debut in Miami soon afterwards, also on Sutherland's recommendation. His position as a leading lyric tenor was consolidated in the years between 1966 and 1972, during which time he first appeared at Milan's La Scala and other major European houses. In 1968, he debuted at New York City's Metropolitan Opera as Rodolfo in Puccini's La bohème. At the Met in 1972, in the role of Tonio in Donizetti's La fille du régiment he earned the title "King of the high Cs" when he sang the aria "Ah mes amis ... pour mon âme". He gained worldwide fame for the brilliance and beauty of his tone, especially into the upper register. He was at his best in bel canto operas, pre-Aida Verdi roles and Puccini works such as La bohème, Tosca and Madama Butterfly. The late 1970s and 1980s saw Pavarotti continue to make significant appearances in the world's foremost opera houses.

Boris Fyodorovich Godunov (Russian: Бори́с Фёдорович Годуно́в, IPA: [bɐˈrʲis ɡədʊˈnof]; c. 1551 – 23 April [O.S. 13 April] 1605) was de facto regent of Russia from c. 1585 to 1598 and then the first non-Rurikid tsar from 1598 to 1605. The end of his reign saw Russia descend into the Time of Troubles.

Boris Godunov was the most noted member of an ancient, now extinct, Russian family of Tatar origin, which came from the Horde to Kostroma in the early 14th century. He was descended from the Tatarian Prince Chet, who went from the Golden Horde to Russia and founded the Ipatiev Monastery in Kostroma. Boris was the son of Feodor Ivanovich Godunov "Krivoy" ("One-eyed") (died, c. 1568–1570) and his wife Stepanida Ivanovna. His older brother Vasily died young and without issue.

Godunov's career began at the court of Ivan the Terrible. He is mentioned in 1570 as taking part in the Serpeisk campaign as an archer of the guard. The following year, he became an oprichnik - a member of Ivan's personal guard and secret police. In 1570/1571, Godunov strengthened his position at court by his marriage to Maria Grigorievna Skuratova-Belskaya, the daughter of oprichniks' head Malyuta Skuratov-Belskiy. In 1580, the Tsar chose Irina Godunova, or Irina (later Alexandra) Feodorovna Godunova (1557 – 26 October/23 November 1603), the sister of Godunov, to be the wife of his second son and eventual heir, the fourteen year old Feodor Ivanovich (1557–1598). On this occasion, Godunov was promoted to the rank of Boyar. On 15 November 1581, he was present at the scene of the Tsar's murder of his own eldest son, the crown prince Ivan. Godunov tried to intervene, but received blows from the Tsar's sceptre. Ivan immediately repented and Godunov rushed to get help for the Tsarevich, who died four days later.

Alfredo Kraus Trujillo (24 November 1927 – 10 September 1999) was a distinguished Spanish tenor of partly Austrian descent, particularly known for the artistry he brought to opera's bel canto roles. He was also considered an outstanding interpreter of the title role in Massenet's opera Werther, and especially of its famous aria, "Pourquoi me réveiller?"

Kraus was born in Las Palmas de Gran Canaria in the Canary Islands of Spain. He began his musical career with piano lessons at the age of four, and he sang in the school choir by age eight. His older brother, Francisco Kraus Trujillo, a baritone, studied music and opera alongside him.

After refining his technique singing Spanish zarzuela on stage in Madrid and Barcelona, Kraus made his professional operatic debut in Cairo during 1956 as the Duke in Rigoletto, which became one of his signature roles. In 1958, he sang Alfredo at the Teatro Nacional de São Carlos in Lisbon in a production of La traviata with Maria Callas, a live recording of which was later released.

Simone Boccanegra (died 1363) was the first doge of Genoa. His story was popularized by Antonio García Gutiérrez's 1843 play Simón Bocanegra and Giuseppe Verdi's 1857 opera Simon Boccanegra. Note the spellings.

Boccanegra was elected doge for life on September 24, 1339, as the candidate of the "popular" Ghibelline faction. Boccanegra was opposed by the aristocratic Guelf faction, representing the old mercantile patriciate, which his first actions excluded from public life. With the old patriciate excluded from power, a new class of mercantile houses arose: Adorno, Guarco, Fregoso, and Montaldo.

During Boccanegra's dogate, Genoese control was extended the length of both the French and Italian Rivieras, with the exception of the Grimaldi holdings in Monaco and Ventimiglia, and Genoese galleys went to the aid of Alfonso XI of Castile in his struggles against the Saracens.

There were constant conspiracies and attempts against Boccanegra's life from the outset. (The first conspirator's head rolled on December 20, 1339.) This led to the establishment of a bodyguard of 103 mounted soldiers. For Boccanegra's security these were drawn from Pisa, the inveterate enemy of Genoa, where, however, Simone's brother Niccolò was "captain of the people", their mother having been a Pisan aristocrat.