In the year 15 BC, Drusus led a military campaign that brought most of the south German foothills of the Alps under Roman rule, but Eastern Bavaria was only occupied after AD 50. The first fort at Passau was established as part of this latter campaign. It was located on the “Ortsspitze” – a sand spit at the confluence of the 3 rivers. The fort was garrisoned by a Roman auxiliary unit. The first Roman finds in the area date to these early years. They include fragments of terra sigillata and a strap end. The earliest military post probably was a fortlet in what is now the Niedernburg and Römerplatz area of Passau. The Romans built similar stations in Weltenburg, Straubing and Osterhofen-Haardorf, as part of a drive to set up a Roman provincial administration. In the following decades, the small military post developed into a full-scale fort housing a cohort of infantrymen; by the second century, it was protected by five defensive ditches. The pottery fragments mounted on the plan show when the ditches were filled. This does not mean that the fort was abandoned, though. It could have remained in operation even without the defensive ditches. The fort on Ortsspitze may have been reinforced or replaced with another one on the Domberg, the Cathedral Hill. Until now, though, archaeologists have not found enough evidence to prove the existence of such a fort on the Domberg.