Michael - someone else asked the original question, and I wasn't criticising anything you'd contributed. (I hadn't realised the Watersons had contributed the 'Shakespeare' verse; I was quite spooked when I happened upon it, leafing through As you like it one day for reasons I forget.)

The hazy chronology on that page you quoted just struck me as a typical example of woozy folkie retro-paganism, something that always irritates me (all right, Les, I'll let it lie in just a minute, OK...). When I sing the Holly and the Ivy I like to introduce it by saying that it's a song that preserves many symbols and images of an ancient faith that was once practised throughout England... a faith called "Christianity". The serious point is that you don't need to go that far back - perhaps to around the time my grandparents were born - to get to a world without electric lighting but with universal observance of Christian ritual. The people Cecil Sharp and Vaughan Williams collected from would have had an immediate understanding of the sentiments of a song like the Holly and the Ivy or the Boar's Head Carol, in a way that we can't any more. (Those sentiments being: (a) "it's really cold and dark out there" and (b) "praise our Lord and Saviour".) Chin-stroking neo-pagan "explanations" of the "symbolism" of these songs just make the past into much more of a foreign country than it was - or maybe it would be closer to the point to say that they make the past easier to understand, by glossing over the taken-for-granted Christian faith which genuinely does seem exotic to us now.

I like the idea of "Aunt Mary Moses" as a codeword for the BVM; not sure if there's anything to support it, but it's a nice folk-explanation at the very least. But I can't see any reason to drag pre-Xtian deities into it.