Tacnazo insurrection Tacnazo insurrection ( October 21 , 1969 ) ( ) was a brief revolt of the Tacna artillery regiment , led by General Roberto Viaux , in what turned out to be a non - violent demonstration against the government of Chilean President Eduardo Frei Montalva . Background . Around mid - 1969 , Brigadier General Roberto Viaux , commander of the First Army Division stationed in Antofagasta , asked " the opinion of the young officers " ( colonels , lieutenant colonels , majors , and captains ) and based on their answers , wrote a letter of petition to the Army Commander - in - chief , General Sergio Castillo , to be presented to President Eduardo Frei Montalva . General Viaux ' s letter said that " " national security and internal peace in our country " " depended on the armed forces , and " " in our judgement " " the Frei administration , like its predecessors , had not concerned itself with keeping a modern army in working order , " " well equipped and taking real part in important decisions " " . The letter demanded that a new government policy toward the armed forces be put into effect , that senior officers ' salaries be adjusted to conform to " " their high social status and national responsibility " " ( in the letter , Viaux complained that " " a general of the Republic earns less than a competent worker at the Chuquicamata copper mine " " , which was true ) , that adequate materiel be purchased , and that the higher echelons of the military hierarchy be given a prominent participatory role in the economic , political , and social development of Chile . General Viaux was confident that his letter would lead to a new dialogue with President Frei , because he had discussed it beforehand with the head of the Army ' s General Staff , Division General Rene Schneider . The letter had even made suggestions about the " participatory " role of the generals in the economic and political life of the country . President Frei , however , did not listen to Rene Schneider , but he did listen to Sergio Castillo , the commander in chief of the Army , an intimate personal friend and a political supporter above all else . General Roberto Viaux was relieved of his command of the First Division on Saturday , October 18 , 1969 , and recalled to Santiago . Events . On Tuesday , October 21 , 1969 , General Viaux became the head of a military insurrection localized in the Tacna Artillery Regiment in Santiago , with the support of the Sub - Officers ' School , the Army War Academy , and part of the 2nd Armored Regiment . At noon on October 21 , it was clear to the reporters covering the incident that General Viaux was counting on the covert support and sympathy of the majority of Santiago ' s officer corps , and that , technically , if Viaux suggested it , there was nothing to prevent the overthrow of Frei and his replacement by a military government without a shot being fired . President Frei reacted by ending the legislative session of the congress , and declaring a State of emergency . However , after a phone conversation with the head of the Army General Staff , René Schneider , General Viaux issued a statement in which he emphasized that " my movement is not against the President of the Republic , " but rather was a last resort " to call attention " to the necessity of putting the Army in the place it deserved . The next day , October 22 , General Viaux ended his rebellion , having elicited the following concessions that were officialized in the so - called " Tacna agreement " : The Army Commander - in - chief , General Sergio Castillo , and the minister of Defense , General Tulio Marambio , would retire . Division General Schneider would become Army Commander - in - chief , and the government would urgently upgrade the salaries of the army personnel and the military budget . General Viaux accepted forced retirement for himself , since General Schneider ' s presence as Commander - in - chief guaranteed that his petitions would be heard . After the negotiations Viaux surrendered himself to General Alfredo Mahn . Aftermath . General Schneider forced Frei to carry out part of Viaux ' s original petition : in January 1970 , the generals ' salaries were raised from an equivalent of six times the minimum wage to twelve times the minimum wage . ( The minimum wage was fixed by law each year for state employees and private enterprise . ) That is , the generals became part of the 2 percent of Chilean households with the highest income . They had belonged to the 10 percent with the highest income before . The military budget was raised by 50 percent for the following fiscal year , and plans to expand the number of officers in the three branches of the armed forces , the military police , and the civilian investigatory police were studied . ( These plans were not put into effect until 1971 , under Salvador Allende ' s administration . ) It was agreed that for their part the corps of Army generals would study long - and short - term " plans of action " to put into practice General Viaux ' s demand that " the armed forces be given a real responsibility in solving national problems " . During 1970 this plan was deferred by the generals themselves so they could concentrate on the means of intervening " in search of social peace " , should the political struggle for the presidency erupt into violent confrontations between the various political factions , a situation that kept threatening throughout the year until September 4 , 1970 the day of the presidential elections .