A Xhosa, Mandela was born in Mvezo to the Thembu royal family. He studied law at the University of Fort Hare and the University of the Witwatersrand before working as a lawyer in Johannesburg. There he became involved in anti-colonial and African nationalist politics, joining the ANC and co-founding its Youth League. After the National Party's white-only government established apartheid—a system of racial segregation that privileged whites—he and the ANC committed themselves to the apartheid government's overthrow. Mandela was appointed President of the ANC's Transvaal branch, rising to prominence for his involvement in the 1952 anti-apartheid Defiance Campaign and the 1955 Congress of the People. He was repeatedly arrested for seditious activities and was unsuccessfully prosecuted in the 1956 Treason Trial. Influenced by Marxism, he secretly joined the South African Communist Party (SACP). Although initially committed to non-violent protest, in association with the SACP he co-founded the militant Umkhonto we Sizwe in 1961 and led a sabotage campaign against the government. In 1962, he was arrested for conspiring to overthrow the state and sentenced to life imprisonment in the Rivonia Trial.