[4] A colourful anecdote relates how another overweening castrato star, Caffarelli, rode post-haste to Rome from Naples just to attend incognito his debut; and full of enthusiasm eventually yelled at him: "Bravo, bravissimo Gizziello, it’s Caffariello who's telling you!
"[5] Whatever the case, at the beginning of 1732 he was urgently called upon to replace the castrato Nicolò Grimaldi (Nicolini), who suddenly died on 1 January during the rehearsals of Pergolesi's first opera La Salustia at the Teatro San Bartolomeo in Naples.
[6] Having become a member of the theatre's company, later that year he performed in new operas by Johann Adolph Hasse, Leonardo Leo and Francesco Mancini,[7] and in revivals of Vinci's Catone in Utica and Artaserse.
He sang at many premieres for the best and most famous musicians of his time, including Niccolò Jommelli (Manlio, 1746), Baldassare Galuppi (Artaserse, 1751) and Johann Adolph Hasse (Demetrio, 1747).
Being a very sharp soprano for his time (Handel got him repeatedly to reach up to C6), Conti was not quite well disposed towards abuse of coloratura and he chose rather to turn to better account his fluent and smooth style of rendering and expression: he has thus remained famous as a sentimental and gentle singer, but he also always kept a condition of absolute excellence at vocal virtuosity, even though not so acrobatic as, for instance, that of his contemporary (and friend) Farinelli.