After a stay in the US, Rubens moved to South Africa in the 1950s and become involved in the anti-apartheid movement. While teaching at the South African College of Music in Cape Town, he was the first musician to refuse to play to segregated audiences; during the ANC Treason Trial (1956–1961) he played high-profile concerts to raise money for ANC defendants; and his home in Newlands became a meeting place for other movement members, including Nelson Mandela and Albie Sachs, who recalled: