Variety reports that the film will depict the young Vivaldi, who was a priest, serving as music teacher to the girls at what is described as "a school for the abandoned, illegitimate daughters of Venice's courtesans." (The Ospedale della Piet_, where Vivaldi began teaching shortly after his ordination at age 25 and with which he remained affiliated, off and on, for most of his life, was an all-female orphanage and school; while it is widely assumed that some wealthy and powerful Venetians stashed their illegitimate daughters there, it does seem to have been a genuine orphanage as well.)
The plot of the film will reportedly have Vivaldi, having bonded with his students and brought them to a high musical standard, leading them in a performance of his compositions — including The Four Seasons — before the Pope. (There is no evidence that any such concert actually took place, though the orchestra and choir at the Piet_ under Vivaldi's direction did become famous enough to be a genuine tourist attraction.)
The new film about the Red Priest will be directed by Boris Damast from a script by journalist Steven Freedman; both have spent years studying Vivaldi's life, according to press reports.
In addition to Fiennes, the cast is set to include Malcolm McDowell, Jacqueline Bisset and G_rard Depardieu, according to Variety.