How did the Supreme Court's decision in Plessy v. Ferguson differ from its
later decision in Brown v. Board of Education?

in the Supreme Court case Plessy vs. Ferguson ruled that "separate but equal" facilities for black and white citizens was not a violation of the 14th amendment. However, the 1954 case in Brown vs. Board of Education ruled that "separate but equal" did violate the 14th amendment. Basically they went back on what they said

"they had a large area of land that they owned."