Floria Tosca is supposed to be a beloved Roman opera star, a professional singer (“celebre cantante”). We know that she sings at the theatre and on private stages. It is said several times that she “prays” in the church – never that she sings there.
But it is well known that in the early 1800s in the Papal states it was forbidden for women to sing in churches or in the theatres until 1798—about three years before Tosca is set.
Roles written for women singers, and performed by them in other parts of Italy, were taken in Rome by castratos (male sopranos and altos surgically altered before adolescence so that their voices did not break).
There were many star castratos like Marchesi and Velluti wildly popular with the Roman opera audience.
At the time of Tosca‘s premiere there was still a castrato (Domenico Mustafà) serving as director of the Vatican chapel, which still employed “natural soprani”: the best known was Alessandro Moreschi, who made some recordings.
During Carnival, “exceptional permissions” were possible for the theatre, and the “Roman Carnival” was known for its duration.
In 1798 the Roman Republic took over and castratos were banned by moralistic revolutionaries,
After the fall of the Republic in 1799, the castratos returned, but the women stayed, thus allowing singers like Floria Tosca to make their Rome debuts.

