I've always wondered about this. It is a story-story, a conversation among gods about mortals. It's a bit risque, as the myrtle of Venus was believed to be an aphrodisiac and a common symbol for erotic love from the Renaissance on. That it was to be twined with Bacchus's vine suggests revelry.
The tune is just slightly different from what we are used to, but different in a way that is more 18th C than 19th, certainly.
It has fallen out once already, and so may be removed again. I don't know why youtube does that sometimes.
HT Dan at Chicago Boyz