Rosanna Calvierri was the alias used by the matriarch of a group of Saturnyns fleeing from a crack in time.
Rosanna and her children fled to Venice where she and her eldest son, Francesco, used perception filters to appear human. Here, Rosanna set up a school for girls in order to transform them into Saturnyns, as none of the other females had survived the trip.
In 1580, Amy Pond and Rory Williams attempted to infiltrate the school with the aid of psychic paper. Having seen through their ruse, Rosanna imprisoned Amy and attempted to convert her. After Isabella helped Amy escape, Rosanna had her devoured by her sons before sending the female converts to eliminate the Doctor and his companions. This ultimately led to her race's end when Guido sacrificed himself to destroy the converts. With nothing left to lose, Rosanna activated the final phase of her plan, creating a storm of boiling rain to sink Venice. However, the Doctor disabled her machinery, leaving her plans in tatters. With no hope of rebuilding her species and her perception filter broken, Rosanna threw herself into the canal, where her children, not recognising her in human form, devoured her. (TV: The Vampires of Venice)
