She created numerous soprano roles in operas and oratorios by Fux, Caldara, and her second husband, Francesco Bartolomeo Conti and was reputedly the highest paid musician in Vienna at the time.
Maria spent her entire childhood and youth at the court of Queen Christina where she was trained as a singer and was known by the diminutive "Mariuccia".
By the late 1680s there are records of her regularly performing in private musical evenings at Queen Christina's court in Rome.
[4] According to Francesco Conti's biographer Hermine Williams, Castelnovo was from an aristocratic family and his full name was Mallo di Castelnuovo.
She also appeared in Venice, Genoa, Casale Monferrato, Livorno, Modena, and Bologna before moving to Vienna in 1710 where she became the prima donna of Emperior Charles VI's court theatre.