brass buckle

Hi guys, So earlier I was detecting at an old (I mean old) church site near my house and I dug this up. At first I thought it was some sort of buckle but now I'm not so sure. It has some sort of spinner or lock on the left side. It's made of brass and It's roughly 2"x2" . Any ideas would be...

I went to a new location to metal detect at, but the second I got there it realized that going there might have been a mistake. On the maps this place had looked so good, and it was right in the middle of a colonial town. As I walked down the trail I could already see junk on the surface. There...