According to this website (http://www.history.com/topics/rosa-parks) on December 21, 1955 is the day when the Montgomery bus boycott happens. The way it happened is when she entered the bus and sat down and Black people were supposed to sit in the back. Then a white man boarded the bus and the bus driver told her to move to the back, but she just sat there and refused to move. The driver called the police and they arrested Rosa Parks. However on this website (http://www.thehenryford.org/exhibits/rosaparks/story.asp) it explained that the bus was filled with people and 4 black people was near, her and they had to move to the back. So there’s a difference between both sources.
Referring to this website (http://students.spsu.edu/asemenov/overview.html) it said there was another person who was sent to jail doing the exact thing like Rosa Parks. "Another Negro woman has been arrested and thrown in jail because she refused to get up out of her seat on the bus for a white person to sit down. It is the second time since the Claudette Colvin case that a Negro woman has been arrested for the same thing. This has to be stopped. Negroes have rights, too, for if Negroes did not ride the buses, they could not operate. Three-fourths of the riders are Negroes, yet we are arrested, or have to stand