Isabella Romola de Medici (1542 - 1576) was the daughter of Cosimo I de Medici, first Grand Duke of Tuscany, and Eleonora di Toledo. To secure a relationship with the powerful Orsinis, Isabella's father arranged her marriage to Paolo Giordano I Orsini when she was 16. Following the death of her father, Isabella was probably murdered, with the complicity of her husband and brother, and in retribution for her relationship with Paolo Giordano's cousin Troilo Orsini.