Jordan's King Abdullah II on Thursday officially named his elder son, Hussein, 15, as crown prince in a royal decree, the palace announced.When he became king in February 1999 after the death of his father, Hussein bin Talal, Abdullah named his brother Hamza as crown prince in keeping with their father's wishes.But five years later, he withdrew the nomination, leaving Hussein as de facto crown prince but without an official appointment.Under Jordan's constitution, the post of crown prince goes to the eldest son of the king, who retains the option of naming a brother. King Hussein replaced his brother Hassan with Abdullah just days before his death.King Abdullah and his wife, Queen Rania, have two boys and two girls.