Round Brooch - Ring Brooches were common in Europe throughout the 13th-15th centuries.
These small round brooches were frequently used to close the collar of a gown. They also work very well to pin up skirts or fasten light weight cloaks.

Measurements:
The outer diameter of this brooch is 3 cm and the inner diameter is 1.5 cm.
Weight= 13g

This style of brooch was very common and can be found in museum collections around Europe.
It is based on an example from an archeological site and can be seen on page 234 of the book by V. V. Sedov. "Eastern Slavs in the VI-XIII centuries."