The reason I said it's an elephant and not a priest, is that why would a priest be in the middle of a battle? You have rooks as siege towers or catapults (or some war machine), pawns as infantry squads, and knights as cavalry squads. It would only make sense for the bishops to be war elephants rather than priests.
Why would a queen be in the middle of battle? No one is arguing with the origins of the pieces. But the modern names come from England. They adapted the Arabic and Indian names to fit the roles of the royal court, which would include the bishop.
If you like Wikipedia, the Bishop name for the piece didn't appear until the 16th Century.
https://en.wikipedia.org/wiki/Bishop_(chess)