What did the Supreme Court decision in Brown v. Board of Education do?

The Supreme Court decision in Brown v. Board of Education in 1954 ruled that segregation in public schools was unconstitutional, thus overturning the previous "separate but equal" doctrine established in the Plessy v. Ferguson case. The Brown v. Board decision paved the way for the desegregation of public schools and helped to establish the legal foundation for the Civil Rights Movement.