Der römische Militärplatz Submuntorium/Burghöfe an der oberen Donau
The Roman site Submuntorium/Burghöfe is situated on a plateau of a promontory above the valleys of the rivers Danube and Lech, about 30 km north of the provincial capital of Augusta Vindelicum/Augsburg. It represents one of the most important military sites of the province of Raetia during the early and late Roman periods. From 2001–2007, four excavation seasons, including a geophysical and a field survey, were conducted on the so-called east plateau, a spur of the promontory, as well as on the tip of the spur by the University of Munich. Research focussed on the late Roman fortification and its period of occupation. However, it also offered new information on the early Roman military sites and the extension of the civil settlement (vicus) in the 1st c. AD. One of the most important results is the verification of a fortification of 1.5 ha, consisting of a curved system of two defensive ditches and possibly an accompanying turf or earth and timber rampart. They pre-date the well-known auxiliary fort and should belong to the early 40s of the 1st c. AD. After the abandonment of the fortification and the construction of the auxiliary fort the so-called eastern vicus developed in this area. It was destroyed by fire around AD 80.
The late Roman fort and its 1.5 m wide opus caementicium wall were documented in various areas on the tip of the spur. The fortification dates to the late 290s AD and belongs to a group of forts that were built around AD 300 as part of an official Tetrarchic building programme in Raetia. The Notitia Dignitatum mentions the deployment of a mounted unit and a detachment of the legio III Italica at Submuntorium. During the Constantinian period, an artisanal settlement of combined workshops and living quarters processed ferrous and non-ferrous metals. It was fortified around AD 350 with a defensive ditch and an earth or turf rampart. The small finds provide evidence of the period of occupation of the late Roman fortification and the adjacent vicus as well as of the military and civil population. Two gold coins of Leo I probably attest a military presence during the third quarter of the 5th c. AD. It seems likely that the security of the frontiers and military structures of the provinces Raetia prima et secunda, both part of the Italian diocese Italia annonaria, were maintained until the death of Aetius in AD 454. Raetia may have consequently acted as a type of defensive glacis for the Italian prefecture until the abdication of the last Roman emperor of the western empire, Romulus Augustulus.