Rosa Parks, a member of the AME Church in Montgomery, had worked as a secretary with the NAACP for years. On December 1, 1955, she refused to sit in the back of a public bus. The NAACP planned to make Parks the test case for the constitutionality of segregated bus travel. However, the black people of Montgomery turned the test case into a mass boycott of Montgomery's bus system. The boycott lasted over a year, surviving threats, indictments, bombings of church leaders' homes, and long walks. Finally, on December 20, 1956, the Supreme Court desegregated city buses in Montgomery. Martin Luther King, Jr. rode the movement to national prominence, making Mrs. Parks' victory the first blow against the wall of southern segregation.