Which commander-in-chief of the Hellenic Army also instituted The Royal Order of George?
Order of George I: The Royal Order of George I (Greek: Βασιλικόν Τάγμα Γεωργίου Α' ) is a Greek order instituted by King Constantine I in 1915. Constantine I of Greece:  He was commander-in-chief of the Hellenic Army during the unsuccessful Greco-Turkish War of 1897 and led the Greek forces during the successful Balkan Wars of 1912–1913, in which Greece expanded to include Thessaloniki, doubling in area and population.
Constantine I