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). The term is also used for later silver coins produced in central Europe during the early Middle Ages.
There are also similar pieces from the neighboring Huns (and from their invasion of India) in the style of Gupta and Roman coinage.
Read more about Bracteate: Gold Bracteates From The Migration Period, Early Medieval Bracteates, Indian-style Bracteates