It’s Halloween today, so here’s a very brief history of the holiday. A complete history would probably run to several volumes.
Halloween’s a lot more than just a modern excuse for kids to get sweets. It goes back to the Celtic festival of Samhain, marking the transition of summer into winter and the night when your dead ancestors might come back to check up on you. Your ancestors wouldn’t be dangerous, unless you came from a very dodgy family, but you could never tell what other spirits might hitch-hike in with them. The tradition of telling horror stories probably originated as a means of controlling evil spirits by naming them.
This feast of the honoured dead was transformed by the early Christian church into the festival of All Saints (or All Hallows). The reason we celebrate it the night before is simply because the Celtic calendar, as the Jewish one still does, had its days running from sunset to sunset.
Halloween became unpopular after the Reformation, since it was seen as both Catholic and pagan, so when an opportunity arose, the festival was moved a few days and disguised as Guy Fawkes Night. Samhain had involved lighting bonfires (which burn bones) and balefires (which burn wood) with a straw figure on them. It’s possible that, at one time, this was an actual human sacrifice, though it’s difficult to be sure. Most religions speak of their symbolic rituals as if they were literal, and it’s possible that the sacrifice has always been a token one.
Halloween largely died out in Britain (when I was a kid, it really just meant there’d be a ghost story on TV) but some of its traditions had been exported to America. This included “souling”, where the children of the village went round to each house demanding specially baked soul cakes and other treats, in return for wishing luck on the household for the coming year. It’s not clear where the “trick” aspect came from – perhaps a graphic demonstration of what it meant not to have the ritual luck.
Until quite recently, Trick or Treating was exclusively American, but Hollywood films of the 80s and 90s, such as E.T., introduced British children to the concept. Now, it seems to have largely replaced Penny for the Guy in most places, but this is really just a tradition coming home.