House of Farnese
In order to cement relations between the House of Farnese, Maria's older sister Isabella d'Este had been married to Ranuccio Farnese, Duke of Parma, son of Odoardo Farnese, Duke of Parma and Margherita de' Medici in 1664. Isabella died in 1666 as a result of childbirth. In order to preserve the union between the two ducal houses, the unmarried Maria became Ranuccio's next consort.