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 too communist, and believed that its leadership should have hidden its Marxist orientation instead of promoting it. According to the official version of events, the majority of the PDPA Central Committee rejected Karmal's criticism. The vote was a close one, and it is reported that Taraki expanded the Central Committee to win the vote; this plan resulted in eight of the new members becoming politically unaligned with and one switching to the Parchamite side. Karmal and half the PDPA Central Committee left the PDPA to establish a Parchamite-led PDPA. Officially the split was caused by ideological differences, but the party