A metal cloak pin popular in northern Europe, circular in shape but with a break in the ring so that the pin may pass through and be twisted to lock it.
Are from early Celtic times and are a circular Brooch with a long pin which were used to fasten two pieces of cloth together. The earliest-known piece is the Hunterston brooch from A.D. 700
almost annular or circular closure for a cloak, with a small gap to allow the insertion of fabric held in place by a pin which bisects the circle. Later developed into the ring brooch where the circle was completely closed.