The circle in Celtic history represents both eternity and the sun. The knot-work represents unending love and spiritual growth because it goes on forever. It was worn by both men and women starting in the Iron Age, to pin cloaks, hoods, scarfs, ties, etc. and was a valued accessory to both Celtic and Viking age cultures.
This is a Penannular Brooch and is used similar to a belt buckle, but without making any permanent hole. You fold your fabric through, then turn the circle to fasten the pin to the side. It is finished Antique Brass and measures 2 1/4" Diameter