After the arrest of Rosa Parks on December 1, 1955, for refusing to give up her seat on a bus to a white man, Abernathy, then a member of the Montgomery NAACP), collaborated with King to create the Montgomery Improvement Association, which organized the Montgomery bus boycott. Along with fellow English professor Jo Ann Robinson, they called for and distributed flyers asking the black citizens of Montgomery to stay off the buses. The boycott attracted national attention, and a federal court case that ended on December 17, 1956, when the U.S. Supreme Court, in Browder v. Gayle, upheld an earlier District Court decision that the bus segregation was unconstitutional. The 381-day transit boycott, challenging the "Jim Crow" segregation laws, had been successful. And on December 20, 1956, the boycott came to an end.