Costanza Farnese was a daughter of Alessandro Farnese and Silvia Ruffini. Born before her father became Pope Paul III, her siblings were Pier Luigi, Paul, Ranuccio and Lucrezia.
She married Bosio II Sforza, count of Santa Fiora e Cotignola, they had:
Sforza Sforza, whose children were:
Alessandro, 7th count of Santa Fiora, duke of Seni and prince of Valmontone, father of cardinal Federico Sforza.
Mario, count of S. Fiora, married Fulvia Conti
Faustina Sforza, married Muzio Sforza of Caravaggio
Francesca Sforza, married Girolamo Orsini
Camilla, married Besso Ferrero of Masserano