Search for: [Abstract = "Over the period of X \- early XIV c., the German Empire had the rights of superiority over the Piasts' Poland, which involved tributes and loyalty oaths by its rulers. The origin of those rights has so far been chiefly sought in the Empire' s power and their periodical appearance and reality was supposed to reflect the then balance of powers. At the beginning, during Mieszko I reign, those rights pertained to certain part of Poland, but then they were supposed to apply to the whole of the country."]