In 1964, thanks to a series of investigation and test digs realised in the territory just south of the Basilica of San Severo, a 3-metre-large and uninterrupted wall section was discovered two meters under the ground. The structure was interrupted beyond the railway line, where during the excavations in 1881 some evidence of a 5-metre-large street probably leading to an urban gateway was found. The research was brought forward with an excavation campaign in 2006, carried out through the realisation of explorative trenches and soundings in the ground that confirmed the presence of the wall. In the major excavation, the wall is connected to a large brick-built circular structure, probably a defensive tower. Research confirm that during the 3rd and 4th centuries AD Classe was armed with a defensive city wall that maintained its function from the 5th to the 10th century.
The structure is located 700 metres east of the Ancient Port of Classe and is part of the ancient walls of the town, an area beside the city that was intended for a specific purpose – a city port. This area was an important destination for people, goods and ships, as well as a residential area for sailors.