Babrak Karmal befriended fellow inmate Mir Akbar Khyber, who introduced Karmal to Marxism. Karmal changed his name from Sultan Hussein to Babrak Karmal, which means "Comrade of the Workers'" in Pashtun, to disassociate himself from his bourgeois background. When he was released from prison, he continued his activities in the student union, and began to promote Marxism. Karmal spent the rest of the 1950s and the early 1960s becoming involved with Marxist organizations, of which there were at least four in Afghanistan at the time; two of the four were established by Karmal. When the 1964 Afghan Provisional Constitution, which legalised the
Babrak Karmal pre-recorded speech to the Afghan people was broadcast via Radio Kabul from Tashkent in the Uzbek SSR (the radio wavelength was changed to that of Kabul), saying: "Today the torture machine of Amin has been smashed, his accomplices – the primitive executioners, usurpers and murderers of tens of thousand of our fellow countrymen – fathers, mothers, sisters, brothers, sons and daughters, children and old people ..." Karmal was not in Kabul when the speech was broadcast; he was in Bagram, protected by the KGB. That evening Yuri Andropov, the Chairman of the KGB, congratulated Karmal on his rise to the