Maria Christina (märēˈä krēstēˈnä) [key], 1806–78, queen of Spain, daughter of Francis I of the Two Sicilies. The fourth wife of Ferdinand VII, she persuaded him to confirm (1833) the original revocation (1789) of the Salic law to allow their daughter Isabella to succeed him. At the king's death (1833) Maria Christina became regent for Isabella II. In the Carlist Wars (see Carlists) that this succession provoked, she was aided by the liberals, but the frequent changes in the constitution alienated their support. The opposition of Espartero forced her to resign the regency, and she went to France (1840). She returned after Espartero's overthrow (1843) and regained influence. She had to yield to Espartero again in 1854 but remained a powerful figure to the end of Isabella's turbulent reign in 1868.