A bracteate (from the Latin bractea, a thin piece of metal) is a flat, thin, single-sided gold medal worn as jewelry that was produced in Northern Europe predominantly during the Migration Period of the Germanic Iron Age (including the Vendel era in Sweden). Bracteate coins are also known from the medieval kingdoms around the Bay of Bengal, such as Harikela and Mon city-states. The term is also used for thin discs, especially in gold, to be sewn onto clothing in the ancient world, as found for example in the ancient Persian Oxus treasure, and also later silver coins produced in central Europe during the Early Middle Ages. Source: Wikipedia (en)