11 January 1963
On 11 January 1963, African National Congress (ANC) member, Walter Sisulu attended a secret meeting at the house of George Xarile together with F. Van Rensburg, a shift boss from Vlakfontein mine. It is understood that Van Rensburg made bombs for Sisulu, presumably from dynamite. At the time of the meeting the ANC and other liberation movements were banned under the Unlawful Organisations Act. All “illegal organisations” were on 7 April 1960 banned. Six months later, Sisulu and members of the Umkhonto we Sizwe High Command were arrested at Liliesleaf Farm, and placed in solitary confinement for 88 days. Following the verdict on 12 June 1964, Sisulu and other treason trialists were taken to Robben Island, where he spent 25 years before being released in 1989. 
References

O’Malley P. ‘1963’, from Nelson Mandela Foundation, [online], Available at www.nelsonmandela.org [Accessed: 01 December 2011]|African History, ‘Walter Max Sisulu’, [online], Available at www.africanhistory.about.com [Accessed: 01 December 2011]