Several years ago I sat down to learn a solo fingerstyle guitar arrangement of the hymn A Mighty Fortress Is Our God off of an Ed Gerhard CD. In the process I was surprised to discover that the tune was in 5/4 time. I don't know if it is always played that way, but it sounded very natural, and very much like other renditions I had heard over the years (including its use as the opening music for the children's claymation religious program Davey And Goliath, which Americans of a certain age will remember).