Short answers, pulled from the story.
Donizetti is best known for his operas, of which he composed roughly seventy-five. His most celebrated works today are Lucia di Lammermoor (1835), L'elisir d'amore (1832), Don Pasquale (1843), and La fille du regiment (1840).
Donizetti was born on the 29th of November 1797 in the Borgo Canale quarter of Bergamo, Lombardy, just outside the city walls. His father Andrea was the caretaker of the town pawnshop, and the family had no tradition of music.
Simone Mayr was a German composer who became maestro di cappella at Bergamo's principal church in 1802 and founded the Lezioni Caritatevoli school in 1805, where Donizetti received his early musical training. Mayr repeatedly intervened to keep the young Donizetti enrolled, secured funding and letters of recommendation for his studies in Bologna, and is buried near Donizetti in Bergamo's Basilica of Santa Maria Maggiore.
Donizetti was diagnosed with cerebro-spinal syphilis and severe mental illness in August 1845. By February 1846 physicians concluded he could no longer make sound decisions, and he was confined to the Maison Esquirol at Ivry-sur-Seine outside Paris. He was returned to Bergamo in October 1847 and died there on the 8th of April 1848 following a bout of apoplexy.
Donizetti chafed against censorship in Italy, particularly in Naples, and saw Paris as offering greater freedom to choose subjects, larger fees, and greater prestige. The final break came in October 1838 when the King of Naples banned his opera Poliuto as an inappropriate treatment of a sacred subject.
Fifty-one of Donizetti's operas were presented in Naples, the result of a long working relationship with the city's theatres beginning in 1822 with an offer from impresario Domenico Barbaja of the Teatro di San Carlo.