It's been called that for closer to 200 years according to the article Maurice alluded to. Got it's name from Charles II's nickname that his mother gave him, apparently.
20+ pubs in the UK with "Black Boy" in its name. I went to "The Black Boy" in Hull after a game a few years ago and thought "what the f**k?! Surely you can't have a pub called that!" Weirdest thing was that the doorman was a black guy
Anyway... times have changed... unfortunately, it seems, for a lot of people who would rather we were still neanderthals. I mean, the invention of fire would be "changing history" for those who were happy being cold and eating raw meat etc.