Italian composer (1797-1848) known as a leading composer of the bel canto opera style. ALS in French, signed "Donizetti," one page, 4.75 x 7.25, blindstamped monogram letterhead, no date but circa 1839-1840. Letter thanking his correspondent for his assistance, in full (translated): "I am very grateful for everything you are doing for me; I accept the success of Lucia [di Lammermoor] as an anticipation of the success of the Martyrs, that should begin rehearsing after Ruolz's Vendetta." In fine condition, with one repaired edge tear. Lucia di Lammermoor was first performed in French translation at the Theatre de la Renaissance on August 3, 1839. Donizetti was living in Paris at this time and was preparing a revision of his opera Poliuto for the Paris Opera, which premiered as Les Martyrs in April 1840.