During the Axis occupation of Greece (1941–1945) Ritsos became a member of the EAM (National Liberation Front) and authored several poems for the Greek Resistance. These include a booklet of poems dedicated to the resistance leader Aris Velouchiotis, written immediately upon the latter's death on 16 June 1945. Ritsos also supported the Left in the subsequent Civil War (1946-1949); in 1948 he was arrested and spent four years in prison camps. In the 1950s "Epitaphios", set to music by Mikis Theodorakis, became the anthem of the Greek Left.