disadvantage—offered a ceasefire, the Pretoria Minute, for which he was widely criticised by MK activists. He spent much time trying to unify and build the ANC, appearing at a Johannesburg conference in December attended by 1,600 delegates, many of whom found him more moderate than expected. At the ANC's July 1991 national conference in Durban, Mandela admitted that the party had faults and announced his aim to build a "strong and well-oiled task force" for securing majority rule. At the conference, he was elected ANC President, replacing the ailing Tambo, and a 50-strong multiracial, mixed gendered national executive was elected. Mandela was given an office in the newly purchased ANC headquarters at Shell House, Johannesburg, and moved into Winnie's large Soweto home. Their marriage was increasingly strained as he learned of her affair with Dali Mpofu, but he supported her during her trial for kidnapping and assault. He gained funding for her defence from the International Defence and Aid Fund for Southern Africa and from Libyan leader Muammar Gaddafi, but, in June 1991, she was found guilty and sentenced to six years in prison, reduced to two on appeal. On 13 April 1992, Mandela publicly announced his separation from Winnie. The ANC forced her to step down from the national executive for misappropriating ANC funds; Mandela moved into the mostly white Johannesburg suburb of Houghton. Mandela's prospects for a peaceful transition were further damaged by an increase in "black-on-black" violence, particularly between ANC and Inkatha supporters in KwaZulu-Natal, which resulted in thousands of deaths. Mandela met with Inkatha leader Buthelezi, but the ANC prevented further negotiations on the issue. Mandela argued that there was a "third force" within the state intelligence services fuelling the "slaughter of the people" and openly blamed de Klerk—whom he increasingly distrusted—for the Sebokeng massacre. In September 1991, a national peace conference was held in Johannesburg at which Mandela, Buthelezi and de Klerk signed a peace accord, though the violence continued. CODESA talks: 1991–92 The Convention for a Democratic South Africa (CODESA) began in December 1991 at the Johannesburg World Trade Centre, attended by 228 delegates from 19 political parties. Although Cyril Ramaphosa led the ANC's delegation, Mandela remained a key figure. After de Klerk used the closing speech to condemn the ANC's violence, he took to the stage to denounce de Klerk as the "head of an illegitimate, discredited minority regime". Dominated by the National