Roman coins were used throughout the Roman Empire, which reached from Britain to Africa and from Spain to Arabia. The Austrian province of Styria, part of the Roman province Noricum, belonged to the Roman currency area, and Roman coins circulated there regularly, forming the basis of the monetary economy. For this study, each ancient coin ever found in Styria was registered; they were then entered into a digital database and mapped geographically. This has provided the basis for a reconstruction of coin circulation, currency policies, and the economic, social and migration history from the 1st century BC to the 5th century AD. Important information could thus be gained about the changeable economic development of the various Roman settlements in Styria. In some locations, because of external threats — as for example the Marcomannic invasion from the north — one finds interruptions in the supply of money.