Under which government did this Italian classical composer, conductor, and teacher that became a source of inspiration for "A Little Nightmare Music" pursue his career?
A Little Nightmare Music:  The opera is described as being "based on a dream he had December 4, 1791, the night that Wolfgang Amadeus Mozart died and Antonio Salieri didn't." Antonio Salieri: Antonio Salieri (] ; 18 August 17507 May 1825) was an Italian classical composer, conductor, and teacher. Antonio Salieri:  He was born in Legnago, south of Verona, in the Republic of Venice, and spent his adult life and career as a subject of the Habsburg Monarchy.
the Habsburg Monarchy