Highly detailed Victorian brass back plates - there are a pair of them

I am uncertain exactly what these would have been used on - I do also have some square ones listed so please see my other listings 

Possibly back plates on door knobs although the reverse also has decorative intricate detail and I don't think they would usually go to that much trouble on back plates 

If you know please message me 

Reverse of these also us beautifully detailed with flier d lys type symbols 

Measures 79mm diameter and central hole is 24mm diameter