The Claustra Alpium Iuliarum. A Frontier for Monetary Circulation in the Late Roman Period

According to the pattern of coin distribution across the northeastern border of the Diocesis Italiciana, the defensive system known as Claustra Alpium Iuliarum became a closed frontier for the circulation of coins in time of political unrest. This was the result of the strict control of monetary circulation pursued by the Late Roman usurpers. Coin production was also carefully organized to secure a regular supply to their dominions. Apart from the numismatic aspect, this evidence can shed further light on the Late Roman usurpations from a historical and economic point of view.