The concept of civil rights is of recent origin, though it represents the centuries-old struggle of African-Americans against unfair treatment. Its use began after the end of the US Civil War, when the 14th Amendment was passed to address the issues faced by former African-American slaves who were freed by the war. Later, the term became popular following the Civil Rights Movement of the 1950s and '60s, after which the Civil Rights Act of 1964 was passed.