Antonio Salieri (1750-1825) was one of the most acclaimed operatic composers of his time, and his pupils included Schubert, Liszt and Beethoven. He served a long and distinguished career -- first as resident composer and later as music director in the imperial court, of Vienna -- and composed 39 operas, numerous pieces of church music, a few symphonies and concertos. But today he is remembered almost exclusively for the rumor, circulated in Vienna during the later years of his life, that he poisoned his younger rival, Wolfgang Amadeus Mozart.

That rumor was made into a drama, "Mozart and Salieri," by Pushkin and transformed into an opera by Rimsky-Korsakov. It is no longer taken seriously by any Mozart scholar, but it has provided the background for "Amadeus," the latest play by Peter Shaffer, author of "Equus." Shaffer does not contradict the scholarly consensus that Salieri was innocent of poisoning, but he insists that "Mozart died believing someone had poisoned him" and his play clearly proposes that Salieri poisoned Mozart's career if not his body.

For this charge the evidence is impressive, and Shaffer assembles it like a prosecuting attorney. Five years older than Mozart, Salieri was already well established as the leading composer of Italian opera in Vienna long before Mozart moved there in 1881. He had been court composer since 1774 and a successful free lance in the Viennese theaters for four years before that. At the time of Mozart's arrival, Emperor Joseph II was trying to launch a new company to produce Singspiels -- German operas with spoken dialogue. Salieri tried his hand in this almost-unexplored form -- and flopped as Shaffer makes clear. Then Mozart's "Abduction From the Seraglio," the first great opera composed in German, made a sensation, Shaffer depicts Salieri -- a notorious intriguer in a city where operatic intrigue was almost a way of life -- launching backstage machinations to destroy Mozart's career.

The production of "Abduction" was delayed almost a year; the librettist published a complaint about changes in the text; there was an organized cabal at the early performances that talked all through the music -- though Mozart notes proudly in a letter that they could not stop the applause after each aria. When the Singspiel project broke down (possibly because of intrigues at court; possibly because there weren't any other composers like Mozart to write for it), Mozart turned his hand to Italian opera with "The Marriage of Figaro," and Salieri might have had a lot more to worry about: This was really his territory, and Mozart had produced a masterpiece. Shaffer shows Salieri trying to have the opera banned because of its revolutionary sentiments (a servant is the hero and a count the prime villain), and his failure.

What saved Salieri's status was the quality of Mozart's music -- too complex and new in form for the frivolous, conservative audiences of the time. In "Amadeus," Shaffer makes the point that Salieri was one of the few people in Vienna who were able to understand completely what Mozart was up to, and this added to his torments and may have inspired his intrigues. This perception offers dramatic possibilities considerably more interesting than a simple whodunit on the question of whether or not Mozart was poisoned by Salieri.