Orphir Round Kirk ...

... next to the Earl's drinking hall (or "Bu") and as mentioned in the Orkneyinga saga:

There was a great drinking-hall at Orphir, with a door in the south wall near the eastern gable, and in front of the hall, just a few paces down from it, stood a fine church. On the left as you came into the hall was a large stone slab, with a lot of big ale vats behind it, and opposite the door was the living room