Fürst (, female form Fürstin, plural Fürsten; from Old High German furisto "der Erste", English "the first", a translation of the Latin princeps) were, since the medieval period, members of the highest nobility who ruled over the Holy Roman Empire and later its former territories, below the ruling Kaiser (emperor) or König (king). A Prince of the Holy Roman Empire was the reigning sovereign ruler, monarch, of an imperial state that held imperial immediacy in the boundaries of the Holy Roman Empire. The territory ruled is referred to in German as a Fürstentum (principality), the family dynasty referred to as a Fürstenhaus (princely house), and the (non-reigning) descendants of a Fürst are titled and referred to in German as Prinz (prince) or Prinzessin (princess).