In 1952 the African National Congress and the South African Indian Congress (SAIC) called all South Africans to stand up against the apartheid government's unjust laws directed at the black African, Indian and coloured population. On April 6, while most white South Africans celebrated the tercentenary of Jan van Riebeeck's arrival at the Cape in 1652, the ANC and SAIC called on black South Africans to observe the day as a "A National Day of Pledge and Prayer". 15 000 people attended in Johannesburg, 10 000 in Cape Town, 10 000 in Durban and 20 000 in Port Elizabeth. The meeting in Port Elizabethwas led by Professor Z. K. Matthews and by Raymond Mhlaba.