A thought just occurred to me - and I am by no means an expert here or quite as erudite as some of you. But, is it possible that the shelia figure served the same function at some point as the gargolyes later on? A "decoration" that may have served some significant purpose or as has also been speculated here - may have just become "the thing to do."

Peace,
Raven

I'm not really an expert on the subject, but rather a moderately well-informed layman at best. So I can't tell you if most of the Shielas are over the western entrance to the churches where they appear or not.

In general, though, I think it at best a projection of the wishes of modern pagans to assume that the Shielas somehow reference the legends of pagan Ireland, especially given that many of them were likely carved by non-Irish carvers. And that does not account for the shielas in churches in England and Wales, for which any connection to Irish legend would be highly improbable at best.

One point against the survival of ancient paganism theory is that no comparable symbols have ever been found at a pre-Christian site in the British Isles. One would think that if there were some sort of continuity of pagan belief involved, we'd have found something similar by this point. But the best evidence we have suggests that both Britain south of Hadrian's Wall and Ireland in it's entirety were essentially entirely Christian by the time that the Anglo-Saxon invasions started around the Sixth Century CE, so I don't put a lot of credence in that idea.

My personal feeling is that the Shielas are medieval grotesques of unknown meaning which modern pagans are attempting to interpret as having pagan symbolism, on the basis that they imagine that the medieval Church would not have tolerated such a blatantly sexual symbol, and therefore it somehow MUST be pagan. But again, that's a projection of modern morals and attitudes onto people and a culture who did not necessarily share them.