Ferdinand VII was restored to the throne of Spain in March 1814. Like his Italian Bourbon counterpart, his subjects revolted against him in January 1820 and he was forced to grant a constitution. A French army invaded in 1823 and the constitution was revoked. Ferdinand married his fourth wife, Maria Christina, the daughter of Francis I, the Bourbon king of Sicily, in 1829. Despite his many marriages he did not have a son, so in 1833 he was influenced by his wife to abolish the Salic Law so that their daughter, Isabella, could become queen depriving his brother, Don Carlos, of the throne.