In the newest update for EU4, Denmark's monarch, at least while the Kalmar Union persists, is referred to as "Arch King", is this a real title?

by reaperkronos1

His regnal title (at least in English) doesn't have any mention of arch-king. Is this a fabrication of EU4, or a true title used by the leaders of the Kalmar Union?

Duke_In_The_North

During his coronation in ribe he was proclaimed Archirex or Arch-King however his title was not used by his successors