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 for a revolution... I knew that people would not support us if we decided to keep power without such support. For unknown reasons, Karmal was invited back to Kabul by Najibullah, and "for equally obscure reasons Karmal accepted", returning on June 20, 1991. If Najibullah's plan was to strengthen his position within the Watan Party (the renamed PDPA) by appeasing the pro-Karmal Parchamites, he failed - Karmal's apartment became a center for opposition to Najibullah's government. When Najibullah was toppled in 1992, Karmal became the most powerful politician in Kabul through leadership of the Parcham. However, his negotiations with the