Following the end of Reconstruction and the establishment of full citizenship for former slaves, many states started instituting laws that required separate public facilities, such as railroad compartments, for whites and African Americans.
In 1892, a man of mixed race, Homer Plessy, sat down in a whites-only compartment of a railroad car. He was arrested, and each level of the Louisiana court system found him guilty of violating the state’s segregation laws. The state supreme court, however, allowed Plessy’s case to go further in the appeal process.
The case was eventually heard by the US Supreme Court in 1896. The grounds for Plessy’s case rested on the assumption that segregation laws were unconstitutional on the basis of the equal protection clause of the Fourteenth Amendment. Directly from plato