Martin Luther King Jr. (1929–1968) was an American civil rights activist and Baptist minister who led the civil rights movement from 1955 until his assassination in 1968. He worked to end legalized discrimination, especially the Jim Crow laws that mostly affected African Americans, using nonviolence and sometimes civil disobedience. King helped lead marches for voting rights, desegregation and labor rights, and he delivered his "I Have a Dream" speech at the 1963 March on Washington. He won the 1964 Nobel Peace Prize.