has not been recognised by members of the branch descended from Prince Gabriel of Bourbon-Two Sicilies. The legality of this has been disputed by Prince Pedro on the grounds that the succession to the Two Sicilies crown was established in two international treaties (Vienna 1737 and Naples 1759) as well as the Pragmatic Decree of 1759 and the nineteenth century Two Sicilies constitutions and therefore could not be changed by a unilateral act, even by an undisputed head of the royal house. The succession to the Constantinian Grand Mastership was confirmed by an Imperial Bull and a Papal Brief, and by the Bull Militantis Ecclesiae, and required that the Grand Mastership, an ecclesiastical office in canon law, could only be held by males and must pass by primogeniture to the heirs of the House of Farnese; the purported change to the succession by Prince Carlo has not been approved by the Holy See. Ranks of the Order Grades Special Class (This category created by the Order headed by the Duke of Castro and is not considered part of the historical ranks of the Order.) Sovereign Knight Grand Cross with Collar Knight Grand Cross, Special Class Justice Bailiff Knight Grand Cross of Justice with Collar Bailiff Knight Grand Cross of Justice Knight/Dame Grand Cross of Justice Knight/Dame Grand Officer of Justice (The rank of Grand Officer was recently introduced into the ranks of the Order headed by the Duke of Castro) Knight/Dame Commander of Justice, giuspatronato (The rank of Commander was created by the Order headed by the Duke of Castro) Knight/Dame Commander of Justice (The rank of Commander was created by the Order headed by the Duke of Castro) Knight/Dame of Justice Grace or Jure Sanguinis (The name Grace was changed to Jure Sanguinis by Infante Alfonso, Duke of Calabria, when Grand Master.) Knight/Dame Grand Cross of Grace, or Jure Sanguinis Knight/Dame Grand Officer of Grace (recently introduced into the ranks of the Order headed by the Duke of Castro) Knight/Dame Commander of Grace, giuspatronato (The rank of Commander was created by the Order headed by the Duke of Castro) Knight/Dame Commander of Grace (The rank of Commander was created by the Order headed by the Duke of Castro) Knight/Dame of Grace or Jure Sanguinis Merit Knight/Dame Grand Cross of Merit Knight/Dame Grand Officer of Merit, Special Class (recently introduced into the ranks of the Order headed by the Duke