period that expressed his support of the anti-apartheid struggle, along with "Been Gone Far Too Long," "Mama," and "The Coal Train." Songs written after the Soweto uprising were generally political in nature, but used hidden meaning to avoid suppression, especially as the movement against apartheid gained momentum. A song by the band Juluka used a metaphor of fighting bulls to suggest the fall of apartheid. Many songs of this period became so widely known that their lyrics were frequently altered and adapted depending on the circumstances, making their authorship collective. Pianist Abdullah Ibrahim used purely musical techniques to convey subversive messages, by incorporating melodies from freedom songs into his improvisations. Ibrahim also composed "Mannenberg", described as the "most powerful anthem of the struggle in the 1980s", which had no lyrics but drew on a number of aspects of black South African culture, including church music, jazz, marabi, and blues, to create a piece that conveyed a sense of freedom and cultural identity. The importance that the anti-apartheid movement among South African exiles increased in the late 1970s, driven partly by the activities of Mayibuye. The Amandla Cultural Ensemble drew together among militant ANC activities living in Angola and elsewhere in this period, influenced by Mayibuye, as well as the World Black Festival of Arts and Culture that was held in Nigeria in 1977. As with Mayibuye, the group tried to use their performances to raise awareness and generate support for the ANC; however, they relied chiefly on new material composed by their own members, such as Jonas Gwangwa. Popular songs performed by the group were selected for or adapted to a militaristic and faster tone and tempo; at the same time, the tenor of the groups performance tended to be more affirmative, and less antagonistic and sarcastic, than that of Mayibuye. Members often struggled to balance their commitments to the ensemble with their military activities, which were often seen as their primary job; some, such as Nomkhosi Mini, daughter of Vuyisile Mini, were killed in military action while they were performing with Amandla. Such artists also faced pressure to use their performance solely in the service of the political movement, without monetary reward. Amandla had carefully crafted performances of music and theater, with a much larger ensemble than Mayibuye, which included a jazz band. The influence of these groups would last beyond the 1970s: a "Culture and Resistance" conference was