The Roman Ovilava (now Wels) was surrounded by a wall, which was probably built in the 3rd century after the Alemannic invasions (233-235). The wall, which was 4 km long and up to 1.35 m wide, encircled an area of ??92 ha. It consisted of conglomerate rocks.
There were about 50 watchtowers along the wall, which were set up at a distance of about 67 m and had a square ground plan.
Excavations could accurately reconstruct the course of this wall, so that today you have quite an accurate idea of ??the size of the Roman Ovilava. The wall ran along the following streets: To the east: Adlerstraße, Roseggerstraße and Römerwall; in the north: Schubertstraße up to Quergasse; in the west: Bernardingasse and Feldgasse; in the south: There the discoveries could not yet prove the exact course of the former wall. There is legitimate doubt whether there was a wall at that time at all, since the river Traun and a large swampy area already protected the city in the south.