 King Constantine II, still unmarried and childless, thus officially recognised his only unmarried sister, Princess Irene, as heir presumptive (excluding the older sister, Princess Sophia, who was due to become Queen of Spain).Peter remained convinced that the change was illegal and that he would be the rightful heir if the King died without fathering a son.Shortly after the King's marriage to their cousin, Princess Anne-Marie of Denmark, the uninvited Prince Peter called a press conference in Athens and openly questioned the legality of the constitutional amendment.