What was the ruling in Plessy v. Ferguson upheld the legality of?

In Plessy v. Ferguson (1896), the U.S. Supreme Court upheld the legality of racial segregation under the doctrine of "separate but equal." The Court ruled that state laws requiring racial segregation in public facilities did not violate the Equal Protection Clause of the Fourteenth Amendment, thereby legitimizing discriminatory practices. This decision provided a legal foundation for segregation and discrimination against African Americans for decades until it was eventually overturned by Brown v. Board of Education in 1954.