A great illustration of how the slander works: &quot;we can never know&quot;. Of course we do know, to the normal standard of historical proof, that Salieri didn&#x27;t kill Mozart: any sane historian would note the fact that Mozart died after a fairly prolonged illness, that his death wasn&#x27;t considered suspicious at the time by his doctor or his family, and that rumors of Salieri&#x27;s involvement started decades later, and that the supposed &quot;Salieri&#x27;s confession&quot; doesn&#x27;t exist, and would pronounce the case closed. It&#x27;s not a mathematical proof, but that can&#x27;t be the standard by which we dismiss baseless rumors, unless we want to keep around every ridiculous accusation ever made by people who were not even contemporaries to the events.<p>As for the rivalry between Salieri and Mozart, it seems that there was a short period of rivalry while Mozart was trying to establish himself in Vienna, and a longer period of amiable relations and collaboration (such as the music piece now discovered). None of this rose above the expected level (given that they had different musical styles), and it certainly doesn&#x27;t make a composer who was otherwise not known to be involved in murders into a poisoner.