regalia (n.)

1530s, "rights and powers of a king, royal privilege," from Latin regalia "royal things," noun use of neuter plural of regalis from rex (genitive regis) "king," from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule." Meaning "decorations or insignia of an order" first recorded 1670s.