Gina Pietranera, duchess of Sanseverina, is the aunt of Fabrizio del Dongo, the protagonist of Stendhal's novel La Chartreuse de Parme. To be more precise, she is his father's sister, and she is instrumental in his ending up in the Charterhouse, the monastery after which the book is named.
Gina becomes the lover of the Prime Minister of Parma, Count Mosca, undertaking a marriage of convenience at his suggestion as a cover for their affair. Fabrizio has just fought in the Battle of Waterloo on Napoleon's side and is injured and penniless. The rest of his family has renounced him for his role in the battle, but Gina and Mosca concoct a plan for Fabrizio to attend a seminary in Naples, with a view to his becoming Archbishop of Parma. Fabrizio is reluctant but has little choice, and so his ecclesiastical career begins.