Answer:
The Black Codes were bodies of laws established at the level of the state governments of the United States, as internal legislation, intended to limit the citizenship rights of the black population. These groups of standards were drafted and promulgated from from the 1830s, and knew a true validity until well into the twentieth century, when the Movement for civil rights in the United States caused its abolition.
Initially, the "Black Codes" were promulgated in states that had not legalized slavery in their territories but wanted to prevent the free black population from accessing equal rights to whites. However, these norms were limited in scope, since most of the black population in the United States remained a slave until the end of the Civil War and it was not necessary to regulate their legal status because being slaves they were considered as movable property and not as people with basic human rights.
The Emancipation Proclamation of 1863, issued in the middle of the Civil War by President Abraham Lincoln, abolished slavery and meant that the black population of the United States changed their legal status immediately. A large mass of individuals of both sexes, and of all ages, was theoretically considered as US citizens and could therefore access the same rights and benefits recognized to the white population. However, the racism strongly established among broad layers of whites did not disappear, and in fact in the States that had been part of the Confederation racial discrimination was a problem in force for generations, which would not disappear only with a law.