Synopsis from http://www.geocities.com/Vienna/Strasse/2915/amadeus.html
The film spans the life of the protagonist, Antonio Salieri, who has desired, since a child, to be a great composer. He makes a "deal" with God if He will grant him this only wish. Salieri is content with his talent and status in court until a musical rival comes to Vienna, Wolfgang Amadeus Mozart. Salieri brims over with jealousy when he hears Mozart's music and realizes God has blessed Mozart with the gift of music, not him. Salieri becomes obsessed with conspiring against Mozart, God's musical "incarnation", and eventually kills him. Only in the end does Salieri realize he has not defeated God, for Mozart's music endures while Salieri's fades into obscurity.
It is highly fiction that he came with such close contact with Salieri, but so is our community. Anyways, in the film, Salieri was there when Mozart lay there composing all night, and Mozart saw Salieri as a good friend while Salieri had only murderous thoughts of hoping he would die quickly form sickness or overwork or mental trauma etc. Good time for slash - anywhere/anytime they met, especially during the later periods of Mozart's life as depicted in the film as Mozart trusted Salieri much while Salieri secretly had ill-thoughts stemming from envy/jealousy.
The original stage play of the movie "Amadeus" had the cast of Sir Ian Mckellen as Salieri and Tim Curry as Mozart. Here's some trivia and tidbits from http://www.imdb.com/title/tt0086879/trivia
Cast member Simon Callow originally portrayed the part of Mozart in the 1979 stage production.
Meg Tilly was originally cast as Constanze. Shortly before shooting began she injured her leg playing soccer with some children in the street in Prague (where the film was to be shot) and the part had to be re-cast.
Mel Gibson auditioned for the role of Mozart.
The name "Amadeus", which is Mozart's middle name, means "Beloved of God". This choice of title refers to Salieri's conviction that Mozart is God's chosen composer.
Several real (or at least apocryphal) events from Mozart's life were incorporated into the screenplay, including the interlude between the child Mozart and Marie Antionette, and the Emperor's comment that "Abduction from the Seraglio" had "too many notes".
Sets and costumes for the operatic productions were based on sketches of the original costumes and sets used when the operas premiered.
Entire film was shot with natural light. In order to get the proper diffusion of light for some scenes, the DPs covered windows from the outside with tracing paper.
The performance of Don Giovanni in the movie was filmed on the same stage where the opera first appeared.
The concept for Mozart's annoying laugh was taken from references in letters written about him. One described his laugh as "an infectious giddy" while another described it as "like metal scraping glass".
Milos Forman and Peter Shaffer spent four months adapting the very stylized play into a workable script. They added characters such as the priest, maid, archbishop, and mother-in-law; Mozart's character was enlarged beyond Salieri's perceptions; and Salieri's monologues were reworked visually.
Prague (Milos Forman's native city) was ideal as a stand-in for Vienna, as modern television antennas, plastic and asphalt had rarely been introduced under Communist rule.
The baroque Tyl Theater, used in the opera sequences, remained largely unaltered since the 1700s. Eleven huge chandeliers - each with 40 to 60 candles - were suspended through the dome windows by scaffolding built on the roof.
Only four sets needed to be built: Salieri's hospital room, Mozart's apartment, a staircase, and the vaudeville theater. All other locations were found locally.
The music was pre-recorded and played in the background as scenes were filmed. Tom Hulce practiced four hours a day at the piano to appear convincing.
Tim Curry auditioned for the role of Mozart (and played Mozart on Broadway).
Mark Hamill also played the role of Mozart on Broadway and lobbied heavily for the role in the film.
Originally, a very young Kenneth Branagh was cast as Mozart, but Milos Forman changed his mind and decided to go with American actors for the principal roles.
Vincent Schiavelli was informed by director Milos Forman after one take of him walking that, "Television is ruining you."