Plessy and Ferguson were the petitioner and the respondent, respectively, in the famous case of Plessy v. Ferguson in which racial segregation in public accommodations was found to be constitutional.
Homer Plessy was one-eighth black, which made him a black man in the eyes of the law. He was born and lived in New Orleans. He was a shoemaker by profession. He was a member of a civil rights group that chose him as the person to be involved in a test case that would challenge the law that segregated train cars.
John Ferguson was the judge in Plessy's case. He was born and raised in Massachusetts, moving to New Orleans after the Civil War. He was a lawyer and then a judge.