The excavation was undertaken in the area of the ancient town of Classe, on the Mazzotti farm where a magnetometer survey had revealed the existence of a church.

Two trenches and a trial trench circa 100 m long were opened in order to investigate the survey results. In the first trench (7 × 7 m) the robber trench of a semicircular apse was exposed at a depth of circa 2 m from the present ground level. At the same depth the mortar make up for a polychrome mosaic pavement, of which some small patches were preserved in situ, came to light. According to the plan shown by the magnetometer, this apsidal space belonged to a large quadrangular building (35 × 30 m), with two apses on the eastern side, situated a few metres away from the basilica.

A second trench was opened in correspondence with the presbytery area of the ecclesiastical building, in order to check for the presence of an apse that was only visible in some of the magnetometer images. In this case a deep semicircular robber trench was also identified (up to 2.5 m down from ground level). It was completely filled with building rubble from the robbing of the basilica. The basilica’s pavement at this point had been completely removed and cut by a large circular brick-built kiln. This productive structure, of which only the firing floor was preserved, was built after the destruction and robbing of the perimeter walls, some time between the end of the 8th and the 15th century.

This trench aimed to clarify the true dimensions and internal layout of the basilica. The building was 40 m wide and circa 71.4 m long, excluding the apse (8.5 m). In correspondence with the central nave a number of patches of the original polychrome mosaic pavement came to light, and again the robber trenches of the perimeter walls, whose foundations were identified at circa 2 m below ground level. In the previous excavation campaign the floor of the northern nave had been exposed. This paving was in opus sectile with motifs similar to those in the basilica of S. Croce at Ravenna, built in the same period.

The foundations of the north and south perimeter walls were anchored to the stylobates of the central nave by imposing perpendicular structures, placed at circa 15 m apart. These structures were not clearly visible in profile and were still covered by the basilica’s floor levels, in the zones which had not been robbed.

Structures probably belonging to the presbytery enclosure were identified in the middle of the central nave. They had been cut by 15th century robbing.
Lastly, a trench was dug outside the building, on the south side. Here, several structures for draining rainwater from the basilica and a craft working structure were identified. These features were probably linked to pottery and glass production, perhaps part of a larger craft working quarter whose presence is suggested by anomalies in the 2008 magnatometer survey.