Hello Jeerweezer,
Welcome to the GMB, and thanks for an interesting question!
Does the top at the back look as if it could be hung on the wall? If so, I was wondering if it could be something used for holding Holy water, so that it could be used for blessing one's self? Likely for a Roman Catholic within their home. I'm sure they have a name, but it escapes me at the moment.
Kind wishes, Nigel