I had no idea what was behind the mirror--it could be water damage, an exposed fireplace, an envelope of money . . . who knows. I conned the boy into helping me remove the mirror this weekend.
The mirror was really heavy but it came down pretty easily.
Then we just had to remove the wood structure behind the mirror.
Next I just have to clean, patch, sand, and prime that area, and then I can get started on painting the living room. New year's house resolutions, I WILL OWN YOU.