The Hellenic Air Force (HAF; Greek: Πολεμική Αεροπορία , "Polemikí Aeroporía", literally "War Aviation", sometimes abbreviated as ΠΑ) is the air force of Greece (with Hellenic being a synonym for Greek).
 The mission of the Hellenic Air Force is to guard and protect Greek airspace, provide air assistance and support to the Hellenic Army and the Hellenic Navy, as well as the provision of humanitarian aid in Greece and around the world.
 The Hellenic Air Force includes approximately 33,000 active troops, of whom 11,750 are career officers, 14,000 are professional conscripts (ΕΠ.ΟΠ.)
, 7,250 are volunteer conscripts and 1,100 are women.
 During the period of monarchy between 1935–1973 the force was known as the Royal Hellenic Air Force (RHAF) (Greek: Ἑλληνικὴ Βασιλικὴ Ἀεροπορία , "Ellinikí Vasilikí Aeroporía").
 The motto of the Hellenic Air Force is the ancient Greek phrase Αἰὲν Ὑψικρατεῖν ("Aièn Hypsikrateîn", "Always Dominate the Heights"), and the HAF ensign represents a flying eagle in front of the Hellenic Air Force roundel.
 The Hellenic Air Force is one of the three branches of the Hellenic Armed Forces.
Order of the White Eagle was a Royal Order in the Kingdom of Serbia (1883–1918) and the Kingdom of Yugoslavia (1918–1945).
 King Milan I of Serbia instituted the Order of the White Eagle on 23 January 1883, concurrently with the Order of St. Sava.
 The Order had five classes and was conferred on Serbian and Yugoslav citizens for achievements in peace or war, or for special merits to the Crown, the state and nation.
 In the period between 1883 and 1898 Order of the White Eagle was the highest award in the Kingdom of Serbia.
 In 1898 the Royal Order of Miloš the Great took precedence over the White Eagle and in 1904 the former was replaced by the Order of the Karađorđe's Star.
Constantine I (Greek: Κωνσταντῖνος Α΄ , "Konstantínos I"; 2 August [O.S. 21 July] 1868 – 11 January 1923) was King of Greece from 1913 to 1917 and from 1920 to 1922.
 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.
 He succeeded to the throne of Greece on 18 March 1913, following his father's assassination.
The IV Army Corps (Greek: Δ' Σώμα Στρατού, abbr.
 Δ' ΣΣ ) is an army corps of the Hellenic Army.
 Established before the First World War, it served in all conflicts Greece participated in until the German invasion of Greece in 1941.
 Re-established in 1976, it has been guarding the Greco-Turkish land border along the Evros River, and thus the most powerful formation in the Hellenic Army.
The Hellenic Army (Greek: Ελληνικός Στρατός , "Ellinikós Stratós", sometimes abbreviated as ΕΣ), formed in 1828, is the land force of Greece (with Hellenic being a synonym for Greek).
 Along with the Hellenic Air Force (HAF) and the Hellenic Navy (HN), it makes up the Hellenic Armed Forces.
 It is currently the largest branch of the three.
 The army is headed by the chief of the Hellenic Army General Staff (HAGS), which in turn is under the command of Hellenic National Defence General Staff (HNDGS).
The Royal Order of George I (Greek: Βασιλικόν Τάγμα Γεωργίου Α' ) is a Greek order instituted by King Constantine I in 1915.
 Since the monarchy's abolition in 1973, it is considered a dynastic order of the former Greek royal family.
The Army Aviation (Greek: Αεροπορία Στρατού ) is the army aviation branch of the Greek Armed Forces.
 Originally established in 1947 with light artillery spotter and liaison aircraft, the acquisition of transport helicopters from 1969 and especially of the AH-64 Apache attack helicopters in the early 1990s changed the role of the service, which was recognized as the sixth arm of the Hellenic Army in 1996.
 The service is headed by the Army Aviation Directorate (Διεύθυνση Αεροπορίας Στρατού) within the Hellenic Army General Staff, and comprises the Army Aviation School (Σχολή Αεροπορίας Στρατού) and the 1st Army Aviation Brigade (1η Ταξιαρχία Αεροπορίας Στρατού, 1η ΤΑΞΑΣ).
The Hellenic Army General Staff (Greek: Γενικό Επιτελείο Στρατού, abbrev.
 ΓΕΣ ) is the general staff of the Hellenic Army, the terrestrial component of the Greek Armed Forces.
 It was established in 1904.
 Since 1950, the HAGS is subordinated to the Hellenic National Defence General Staff.
 Historically, most Chiefs of Staff have come from the Artillery arm.
The Royal Order of Sahametrei (Khmer:គ្រឿងឥស្សរិយយសលំដាប់សហមេត្រី) is an Chivalric order conferred by the Government of the Kingdom of Cambodia.
 The Royal order of Sahametrei was instituted in three classes on 9 September 1948 and was expanded to five classes on 23 August 1956.
 The order was not used during the Khmer Rouge period and was reinstated on 5 October 1995 by Royal Decree No. 1095/01.
 It is conferred primarily on foreigners who have rendered distinguished services to the King and to the people of Cambodia, particularly in the field of external relations and diplomatic services or, as a token of friendship.
The NATO Rapid Deployable Corps – Greece, abbreviated NRDC-GR, is an operational headquarters of the Hellenic Army, intended for the direction of international operations undertaken by the European Union and NATO.
 The HQ was originally going to replace the III Army Corps of the Hellenic Army altogether, taking control of its rapid response units, but this was changed in 2009, so that the two HQs essentially co-exist as a joint formation, each controlling different units of the old Army Corps.
 The Corps is based in the city of Thessaloniki since 1946.

Question: Which commander-in-chief of the Hellenic Army also instituted The Royal Order of George?
Answer: Constantine I