In Roman times, the civilized world was considered to be those parts of the world occupied or ruled by Roman emperors. The peoples outside the Roman borders were generally nomadic tribes and were called barbarians, a word that originally meant only foreigners or outsiders.
However, in the course of battles, many barbarians proved so cruel and fierce in combat that the word gradually acquired the meaning of savage, its current meaning.
Many of the barbarian tribes originated in the east, and they first encountered coins when they crossed the Danube valley in search of new lands. The coins they encountered at that time were the gold staters of Philip of Macedon, the most widely circulated gold coin in antiquity.
The model: Philip's staters
As they gained ground, the barbarian tribes began to mint their own coins, but always imitating Philip's staters. Later, the imitations were copied over and over again until they ended up bearing little resemblance to the original.
Philip's coins show a head of Apollo on the obverse and a charioteer driving a chariot (drawn by two horses) on the reverse. By the time the copies reached Britain in around 100 BC, Apollo had become a tiny face with a lot of hair, and on the reverse side, a half-dismembered horse was barely visible.
However, it is quite possible that some of these abstractions were intentional and had a mystical or mythological meaning that is unknown to us.
Expansion to the West
As the various tribes settled along the Roman frontiers, they began to receive a steady supply of Roman coins, sometimes obtained through trade, sometimes as booty, and sometimes as bribes from the emperor to keep the frontiers peaceful.
In 476, after the fall of Romulus, the last emperor of the West, the barbarian tribes (Goths, Vandals, and Huns) spread across Western Europe. As they gained control of vast areas of Italy, Gaul, Spain, and North Africa, the barbarian invaders divided the imperial domains into a large number of small kingdoms and began to mint their own coins, copying the Roman model.