House of Este
Born to the General Borso d'Este and his wife Ippolita d'Este, Maria Angela Caterina was the product of a marriage between niece and uncle, her father being a son of Cesare d'Este, Duke of Modena, and her mother a daughter of Prince Luigi d'Este, younger son of Cesare. As a member of the House of Este, she was a "princess of Modena" by birth, her father being the "founder" of a collateral line of the House of Este, the short lived House of Este-Scandiano. She was named after her paternal aunt, Princess Eleonora, who became a nun under the name of Sor Angela Caterina.