Complex sentence: The committee engaged Homer Plessy to test the public accommodations provision of the Louisiana law, an action which led to the "Plessy v. Ferguson" decision by the United States Supreme Court which affirmed the legality of "separate-but-equal" facilities.
Split into simpler sentences: The committee engaged Homer Plessy to test the public accommodations provision of the Louisiana law. Plessy's action ultimately led to the "Plessy v. Ferguson" decision by the United States Supreme Court, which affirmed the legality of "separate-but-equal" facilities.