|“||This is how it works. First, we drink you until you're dry. Then we fill you with our blood. It rages through you like a fire, changing you, until one morning you awake and your humanity is a dream now faded.||„|
|~ Signora Calvierri explaining the process of transforming someone into a Saturnynian to Amy.|
Rosanna Calvierri was the alias of a Saturnynian matriarch that lived in Venice, Italy in 1580. She serves as the main antagonist of the Doctor Who episode "The Vampires of Venice". She is portrayed by Helen McCrory, who also portrayed Narcissa Malfoy in the Harry Potter films.
Rosanna and her children fled to Venice where she and her eldest son, Francesco, used Perception filters to appear human. They had come to the Italian city because of their marine nature and to exploit the fear of the plague. They set up a "school" under her management. It gained fame in the city as a plague-free haven and became fashionable.
Once the girls were in the schools, their blood would be replaced with that of the Saturnyians, and they would be transformed into females of the species, ready to help drown Venice and form a new race with the other male survivors. The Eleventh Doctor disabled her machinery leaving her plans in tatters. With no hope of rebuilding her species and her perception filter broken, Rosanna was stuck in human form. She threw herself into the canal and was devoured by her children because they could not recognise her and thought she was a meal.