Why Yahweh? (Or Allah, or Zeus, etc.)

[John V]

Either way, I see what you're saying. What about something closer to home, like Mithras who I mentioned before, who had a last supper, whose followers had a Holy Communion, who were annointed with oil on their foreheads? Justin Martyr I tell you... I swear he was a closet Mithraist!

The same issue applies to Mithraism. Who received the revelation, and what signs did they provide to support it? We don't know. Actually we know very little about Mithraism, as it was a mystery religion which was passed along orally. They didn't have texts. The description you gave of a typical bas-relief from a Mithraeum was accurate. Interpretation of its symbols are, well, interpretation. People see what they want in them. People who want to see parallels to Christianity see parallels to Christianity. Aside from Mithraeum, the only significant information on Mithraism comes from Christians who were writing against Mithraism.