EOKA B' was a Greek Cypriot right-wing pro-enosis paramilitary organisation formed in 1971 that was supported by the ruling Greek junta which came to power in 1967, overthrowing the legitimate Greek government of Panagiotis Kanellopoulos. When George Grivas returned to Cyprus in 1971 he created EOKA B' in response to President Makarios's apparent failure to deliver on the policy of enosis. He was angered by Makarios's rejection of enosis in 1959, and was further upset when the President reaffirmed this position on re-election in 1968. Grivas then took the reins of EOKA B', planning to overthrow Makarios and achieve enosis through violent means.
Whereas EOKA (1955-59) was seen by the majority of Greek Cypriots as an anti-colonialist freedom-fighter group, EOKA B' did not have the same overwhelming support. The Greek Cypriot population were sceptical as a result of EOKA B's open involvement with the unpopular Greek junta, and after eleven years of independence there had been some cooling of enosist sentiment, brought about partly through Makarios's neutralist leadership of an independent republic. The popularity of EOKA-B fell further after attacks on Greek Cypriot Socialists and supporters of independence, while there was public outrage following a botched assassination attempt on Makarios and the murder of former government minister Polycarpos Georkadjis.
When Grivas died from heart failure on January 27, 1974, the new leadership of EOKA-B increasingly came under the direct control and influence of the military junta in Athens. On 15 July 1974, EOKA B' - with approval of the Greek Dictator Dimitrios Ioannidis -assisted the Cyprus National Guard in overthrowing Makarios and installing Nikos Sampson as President of Cyprus. This action served only to trigger a Turkish military Invasion on July 20 1974 which led to the subsequent and continuing Turkish occupation of more than a third of the island's territory.