It was a local Texas thing for a long time; when it went 'national' I don't know, since most back people didn't know about it either, obviously. It was originally the date slaves here found out the war was over, some few days later than it actually ended, not an uncommon occurrence in rural areas, and nothing to do with the Emancipation Proclamation, which only freed slaves in the southern states, not the 7 or so northern states that had slavery, so all we have here is just more stupidity and ignorance from left wingers and their idiot fans on display, and how poorly black people manage their school systems.