Grigorios Spandidakis Grigorios Spandidakis ( , 1909 – 1996 ) was a Greek Army officer who rose to the rank of Lieutenant General and the post of Chief of the Hellenic Army General Staff in 1965 – 1967 . From this position , he was instrumental in the military preparations that resulted in the coup d ' état of 21 April 1967 and the establishment of the Regime of the Colonels . He served as Deputy Prime Minister and Minister for National Defence in the first government of the new regime , but was dismissed after supporting the failed counter - coup attempt launched by King Constantine II on 13 December 1967 . After the fall of the regime , he was tried and convicted to life imprisonment for his role in it . He secured an early release on health grounds and died in 1996 . Life . Spandidakis was born in Rethymno , Crete , in 1909 . He entered the Hellenic Army Academy , graduating on 5 August 1931 as a Cavalry Second Lieutenant . Promotions followed to Lieutenant in 1935 and Captain in 1938 . Spandidakis fought in the Greco - Italian War , and was wounded during the German invasion of Greece . During the Axis Occupation of Greece , he participated in the " Omiros " resistance group , and in 1944 he fled to the Middle East and joined the elite Sacred Band of the Greek government in exile . In 1946 he was promoted to Major and fought in the first operations of the Greek Civil War . In 1947 he was appointed as the first head of the new Armour School , a post he held until 1949 . Promoted to Lieutenant Colonel in the same year , he was placed for a while as aide de camp to Marshal Alexandros Papagos , followed by command of the 391 Tank Regiment . During the 1950s he was posted in a succession of staff and command posts : Operations Officer of the First Army and of the National Defence General Staff , director of the 1st Staff Office of the NATO HQ in Izmir , CO of the II Tank Battle Command , director of the Army ' s Organization Bureau , director of the Armour Training Centre , and CO of the 20th Armoured Division and later of the I Army Corps . In the process he rose to Colonel ( 1955 ) , Brigadier ( 1959 ) , Major General ( 1961 ) and Lt . General ( 1964 ) . On 9 October 1965 , he was appointed Chief of the Hellenic Army General Staff . From this position , Spandidakis became the driving force behind the Army ' s plans to seize power in view of the ongoing political crisis in the country , under the codename " IERAX II " . The Army hierarchy , supported by King Constantine II , feared the growing influence of the left , particularly after the Apostasy of July 1965 and the rising anti - palace sentiment among the populace . Spandidakis promoted several officers who would later play a leading role in the coup d ' état of 21 April 1967 to key positions ; most notably the then - Lieutenant Colonel Georgios Papadopoulos . In early March 1967 , in view of the oncoming legislative elections in May which the right - wing National Radical Union was widely expected to lose , preparations began for implementing the plan , and Spandidakis postponed a planned visit to the United States . Nevertheless , Spandidakis was caught by surprise by the outbreak of the military putsch of 21 April 1967 , which the group of mid - level officers around Papadopoulos initiated without waiting for authorization by the King and the Army leadership . He was at first arrested by the putschists who replaced him with Odysseas Angelis , but quickly agreed to assist them . His acquiescence was a crucial factor in allowing the coup d ' état to unfold smoothly : he used his authority to persuade the acting CO of the III Army Corps , Brigadier Orestis Vidalis , that the coup was sanctioned by the King , and prevented Vidalis ' formation , the most powerful in the Hellenic Army , from descending upon Athens . The putschists initially planned to name him Prime Minister , but were persuaded by the King to appoint a civilian , the judge Konstantinos Kollias , instead . In the new government , Spandidakis was thus appointed Deputy Prime Minister and Minister of National Defence . When King Constantine II tried to overthrow the junta on 13 December 1967 , Spandidakis was on a NATO summit . He supported the failed attempt , and was dismissed from his offices . After the fall of the junta in 1974 , he was tried and condemned to life imprisonment for his role in the coup d ' état , but released on grounds of ill health . He died in Athens in 1996 .