A very recent study of monetary circulation in Roman Aquileia during Late Antiquity included an analysis of patterns of coin distribution across the north eastern border of the Diocesis Italiciana. It was found that during the period under study the defensive system known as Claustra Alpium Iuliarum became a closed frontier for the circulation of coins between Italy and the Balkans. This area played a key role in the major military events of the Late Roman period and, because of its strategic position and role, most of the usurpers chose Aquileia as headquarters. Within the territory under their authority, the need for a regular supply of their armies imposed a strict control of the monetary production and circulation, in fact, a “monetary autarchy”, documented by the distribution of the coin finds. Apart from the numismatic aspect, this evidence can shed further light on the usurpations.