While studying Spanish in Madrid, Irene met Carlos Hugo, Duke of Parma, the eldest son of Carlist pretender to the Spanish throne, Xavier. In the summer of 1963, Princess Irene secretly converted from Protestantism to Roman Catholicism. The first time the public or the Royal Family knew about the conversion was when a photograph appeared on the front page of an Amsterdam newspaper showing the Princess kneeling to receive communion at a Mass in the Roman Catholic Church of the Geronimites (Los Jerónimos) in Madrid.
Irene’s conversion took place a year before her engagement announcement, but the royal family did not officially announce the news until January 1964. When news leaked out that she was engaged to Prince Carlos Hugo (born 1930), it provoked a Protestant outcry and a constitutional crisis.Although Dutch law did not forbid a Catholic to reign over the Netherlands, Protestant succession was traditional, born out of the 16th-century Eighty Years’ War with Spain and the assassination of William of Orange by a supporter of Philip II of Spain who believed William had betrayed both the Spanish monarch and the Catholic Church.
