Descendants of earlier monarchs and princes are only eligible to succeed if male and descended from King Leopold I in male - line ( i.e. according to agnatic primogeniture ) .
That descendants of all Belgian princesses not descended from Albert II are barred from the throne .
Descendants of earlier monarchs and princes are only eligible to succeed if male and descended from King Leopold I in male - line ( i.e. according to agnatic primogeniture ) , meaning that descendants of all Belgian princesses not descended from Albert II are barred from the throne .