The success of grand opera, from Auber to Verdi, stems also from three generations of exceptional performers. The genre is vocally demanding. Meyerbeer, who spent more than eight years in Italy, from 1816 to 1824, returned thoroughly versed in bel canto. This influenced the works he then produced for Paris, notably Robert le Diable and Les Huguenots, which required a degree of virtuosity denied to all but the most accomplished. Casts brought together all the great names in French singing, both male and female. Adolphe Nourrit, who ended his life at the age of 37, and Gilbert Duprez were among the most famous tenors of their time. Nicholas Prosper Levasseur was cast in the most prestigious bass roles, whilst the soprano Cornélie Falcon, who first performed the roles of Valentine (Les Huguenots) and Rachel (La Juive) triumphed alongside Julie Dorus-Gras and the mezzo-soprano Rosine Stoltz.