Lost for over 200 years, a cantata co-written by classical maestros Wolfgang Amadeus Mozart and Antonio Salieri rang out in public for the first time on Tuesday, shedding new light on their reputed intense rivalry.

The Italian composer was allegedly so jealous of the Austrian prodigy that he once tried to poison him — a claim rejected by experts as the collaboration was performed in Prague.

"The part composed by Mozart is, shall we say, more ingenious and dramatic, while the other two verses are more lyrical," musician Lukas Vendl told reporters after playing the four-minute composition on a harpsichord.

"But it's impossible to deduce from it who was a better composer."

The cantata from 1785 is "key to a new understanding of the relationship between Mozart and Salieri," according to Timo Jouko Herrmann, the German musicologist and composer who found the work.

Herrmann said it suggests the men were "colleagues who worked together" rather than rivals and undermines a legend suggesting that Salieri may have played a role in Mozart's untimely death at 35 in 1791.

Titled Per la ricuperata salute di Offelia (For Ophelia's recovered health) the cantata was jointly composed by Mozart, Salieri and an unknown musician named Cornetti.

It accompanies a libretto by Italian poet Lorenzo Da Ponte and is dedicated to popular English soprano Nancy Storace (1765-1817), who returned to the stage after losing her voice for a spell.

The score lay unidentified in the Czech Museum of Music since the 1950s, but Herrmann was finally able to attribute it to the two composers thanks to access to new information on the Internet, the museum said.