Domenico Gaetano Maria Donizetti (] ; 29 November 1797 – 8 April 1848) was an Italian composer.
 Along with Gioachino Rossini and Vincenzo Bellini, Donizetti was a leading composer of the "bel canto" opera style during the first half of the nineteenth century.
 Donizetti's close association with the bel canto style was undoubtedly an influence on other composers such as Giuseppe Verdi (1813–1901).
Giovanni Battista Rubini (7 April 1794 – 3 March 1854) was an Italian tenor, as famous in his time as Enrico Caruso in a later day.
 His ringing and expressive coloratura dexterity in the highest register of his voice, the "tenorino", inspired the writing of operatic roles which today are almost impossible to cast.
 As a singer Rubini was the major early exponent of the Romantic style of the "bel canto" era of Vincenzo Bellini and Gaetano Donizetti.
Raffaele Mirate (3 September 1815 – November 1895) was a celebrated Italian operatic tenor who had an active career from the 1830s through the 1860s.
 Known for his intelligent phrasing and bright and powerful vocal timbre, he was regarded as an outstanding interpreter of the tenor roles in the early and middle period operas of Giuseppe Verdi.
 He notably created the role of the Duke of Mantua in the world premiere of Verdi's "Rigoletto" in 1851.
 He was also a highly regaurded interpreter of bel canto roles, excelling in the operas of Vincenzo Bellini, Gaetano Donizetti, and Gioachino Rossini.
Allen Sven Oxenburg (July 10, 1927 - July 2, 1992) was an American opera director.
 He notably co-founded the American Opera Society (AOS) in 1950 with conductor Arnold Gamson, serving as the AOS's Artistic Director for two decades.
 He not only ran the administrative side of the AOS, but also was served as the company as stage director, program annotater, libretto translator and score editor.
 His work with the AOS was highly influential in sparking and perpetuating the post World War II bel canto revival, particularly through a number of highly lauded productions of rarely heard works by Gioachino Rossini, Gaetano Donizetti, and Vincenzo Bellini.
Opera Rara is a British non-profit recording company, founded in the early 1970s by American Patric Schmid and Englishman Don White to promote concerts of rare and/or forgotten operas by "bel canto" era composers such as Italian composers Gaetano Donizetti, Giovanni Pacini, Saverio Mercadante, and Federico Ricci, as well as French composers of the 1830s forward such as Giacomo Meyerbeer.
Maria Callas, Commendatore OMRI (Greek: Μαρία Κάλλας ; December 2, 1923 – September 16, 1977), was a Greek-American soprano, and one of the most renowned and influential opera singers of the 20th century.
 Many critics praised her "bel canto" technique, wide-ranging voice and dramatic interpretations.
 Her repertoire ranged from classical "opera seria" to the "bel canto" operas of Donizetti, Bellini and Rossini and further, to the works of Verdi and Puccini; and, in her early career, to the music dramas of Wagner.
 Her musical and dramatic talents led to her being hailed as "La Divina".
The American Opera Society (AOS) was a New York City based musical organization that presented concert and semi-staged performances of operas between 1951 and 1970.
 The company was highly influential in sparking and perpetuating the post World War II bel canto revival, particularly through a number of highly lauded productions of rarely heard works by Gioachino Rossini, Gaetano Donizetti, and Vincenzo Bellini.
 The AOS also presented many operas to the American public for the first time, including the United States premieres of Benjamin Britten's "Billy Budd", Giuseppe Verdi's "Giovanna d'Arco", George Frideric Handel's "Hercules" and Hector Berlioz's "Les troyens" to name just a few.
Gaetano Rossi (18 May 1774 – 25 January 1855) was an Italian opera librettist for several of the well-known "bel canto"-era composers including Gioachino Rossini, Gaetano Donizetti, and Saverio Mercadante in Italy and Giacomo Meyerbeer in one of his early Italian successes.
 Other composers with whom he worked included Simon Mayr, a composer and Donizetti's teacher, as well as the prolific Giovanni Pacini.
Gustave Charpentier (] ; 25 June 1860 – 18 February 1956) was a French composer, best known for his opera "Louise".
Domenico Reina (July 14, 1796 - July 29, 1843) was a Swiss bel canto tenor, notable for creating roles in the operas of Vincenzo Bellini, Gaetano Donizetti, Saverio Mercadante, and other Italian composers.

Question: Who was a lead composer for the "bel canto" opera style, Gustave Charpentier or Gaetano Donizetti?
Answer: Donizetti was a leading composer of the "bel canto" opera style during the first half of the nineteenth century.