Bracteates begin as imitation. In the late Roman period the empire paid, bribed and flattered the peoples on its northern edge, and part of what it sent was gold medallions with the emperor's head in profile. In Scandinavia these were worn, copied, and then copied from the copies, and over a few generations the imperial portrait turned into something with no Roman content left. The head remains, but it acquires a horse-like animal beneath it, a bird beside it, a headdress that is not a diadem, and around the edge a border of stamped triangles and beaded wire. About a thousand of the resulting discs survive, thin enough to be struck from one die into gold foil, with a loop soldered on for wearing.
The classification into types A to F is by what is on the die: a head alone, a head above a quadruped, a rider, a whole figure, and so on. The commonest type is the head above the animal, and the standard interpretation connects it to a healing scene, on the strength of an Old High German charm in which a god heals a horse's leg. That reading, developed at length by Karl Hauck, identifies the head as an early form of Odin and treats the whole class as a devotional and protective object of that cult. It is the dominant reading and it is not universally accepted, with critics arguing that a tenth century German charm is thin ground on which to interpret fifth century Scandinavian imagery.