Justiciarius or justitiarius, a judge), in English history, the title of the chief minister of the Norman and earlier Angevin kings.
Justiciarius meant simply "judge," and was originally applied, as Stubbs points out (Const.
389, note), to any officer of the king's court, to the chief justice, or in a very general way to all and sundry who possessed courts of their own or were qualified to act as judices in the shire-courts, even the style capitalis justiciarius being used of judges of the royal court other than the chief.
That the title summus or capitalis justiciarius, or justiciarius totius Angliae was exclusively applied to the king's chief minister.
Thus Ranulf Flambard, the minister of William II., who was probably the first to exercise the powers of a justiciar, is called justiciarius by Ordericus Vitalis.