In 1830, at the advice of his wife, Maria Christina of Bourbon-Two Sicilies, Ferdinand decreed a Pragmatic Sanction that had the effect of fundamental law in Spain. As a result of the sanction, women were allowed to accede to the Spanish throne, and the succession would fall on Ferdinand's infant daughter, Isabella, rather than to his brother Carlos. Carlos – who disputed the legality of Ferdinand's ability to change the fundamental law of succession in Spain – left the country for Portugal, where he became a guest of Dom Miguel, the absolutist pretender in that country's civil war.