Thanks again to Mac who was most helpful in pointing me in the right direction!
The church where the fresco is located (pictured in my previous post) is St. Jacobus in Urschalling, in the Alps. I came across an article in the travel section of the New York Times which gives details about visiting the town HERE. I want to see this in person!
I have been analyzing early Christian texts and manuscripts as I have been writing a chapter on the holy spirit for my new book, Sex and the Serpent: Why the Sexual Conflicts of the Early Church Still Matter. This artwork adds new dimension to my argument that the original Christian Trinity was the Father, Mother Spirit, and Son. Here is a 12th century fresco in a European church that commemorates this!
That this was covered up by other frescos and now is being interpreted as the three angels that appeared to Abraham (because we all know the mother spirit is not part of the Trinity!) is in line with what I have found in the ancient manuscript and hermeneutical tradition.
Later religious thinkers in traditions obscure those earlier scriptures and art which no longer support their present theology or practice. This was done in manuscript copying, where sentences were altered or deleted to fit current beliefs as the scribe made the new copy of the old text. So the old tradition was erased from the manuscripts just as the old art was covered by new art in St. Jacobus. It was also done hermeneutically, by providing the correct way to read and understand the text just as is now being done by the church who wants the fresco to be seen as Abraham's 3 angelic visitors since it is impossible for their forefathers and foremothers to have a painting of the Trinity with a female holy spirit in their church.
I could go on, but I have to get back to the things on my desk that are pressing me.