The work, an 11-movement piece for soloists, choir, and orchestra called Dixit Dominus, was discovered in Dresden earlier this year by Australian musicologist Janice Stockigt.
Michael Talbot, a Vivaldi expert and professor at Liverpool University, said "In terms of sheer musical quality, this is the most important Vivaldi discovery for about 75 years."
Stockigt found the Vivaldi work at the Sachsische Landesbibiliotek, where she was researching the music of Dresden's 18th-century Catholic Court Church. The work was attributed to composer Baldassarre Galuppi, a younger composer.
"I was checking hands of copyists," Stockigt said, "and looked at one work which had a bass line which yelled Vivaldi at me." She brought the work to Talbot, who agreed that work was by Vivaldi.
Stockigt has speculated that the Venetian shop that transcribed the work filled out an order for sacred music by Galuppi with the Vivaldi work, perhaps supplied by the composer's two nephews, who worked in the shop.
Dixit Dominus has not yet been authenticated, but will be presented to the editorial committee of the Antonio Vivaldi Institute in Venice. A complete performance of the work will take place in Venice in 2006.