A few excavations conducted between 1963 and 1990 in the residential and commercial block to the north of the OLV-church sheds partial light on the construction activities happening in the northern region of the castellum. In the preceding occupation phase, Building B had been a public bathhouse. While there is no evidence for its repair and reuse in the 4th century, neither was it completely demolished in this period. It is likely that there were still upstanding elements to the bathhouse, but if and how they were used by the new occupants remains speculative.
Buildings A and C were discovered by Boagers in 1963 in the back of the houses of Stokstraat 16-18 and are spatially located north of the Building B bathhouse. Building A would have been at some point contemporary to the bathhouse. Its interior contained a sub-floor surface with traces of hypocaust pillars and heating elements, suggesting the floor of the hypocaustum were heated via the tiles and the tubulae. Despite the eastern cellar (room 7a) being infilled, it is suggested by Bogaagers that Building A may still have been in use during the 4th century as the western space (room 7) may have functioned as a hypocaust until the last quarter of the 4th century.
In 1963, Boagers had only uncovered the two protruding apses of Building C, which he dated generally to the 4th century based on coins from 383–395 CE discovered in the fill of this building. But further investigations from 1990 and 1993 at the rear of Stokstraat 14 revealed the building was constructed in the 330’s CE or later and abandoned by 400 CE. The building is nearly 9 meters wide and has two interior spaces ending in the two apses in the south end. The eastern space was initially 11 meters but later expanded to 14 meters long while the western space had a total length of 24 meters. Like building A, there is evidence of a hypocaust floor.
In 1974, Bloemers (1975b) discovered fragmentary 4th century remains under Havenstraat 7-15 and the south of buildings A and C. He found three standing walls, each of a 75 cm thickness and six meters long. They stood on top of a trench that was filled in with rubble on the western side of the former bathhouse B. Bloemers suggests these walls were part of a temporary fortification of the baths shortly after the vicus settlement was destroyed c. 270 CE. Bloemers (1975b) furthermore discovered a hypocaust system of 3.50 by 5.00 meters, with an air channel network and a praefurnium on the northern side. Despite their proximity, it was determined by Bloemers that these building fragments were not connected.
The 1983 Hotel Derlon excavations also provide insights into the interior activities of the castellum. In addition to the western gate, other 4th century activities can be observed. In that time, the former sanctuary had not been demolished but was instead partially reused to construct a 4- to 5-meter-wide barn or barracks against the western rampart wall with an entrance facing north, alongside the main road bisecting the castellum.
In 1996, a large excavation was executed in the garden of the OLV-church by the municipal archaeologist. This site lays inside the late Roman fortress. Archaeological finds from the pro-Roman period up to the 13th century were found. For the time of the castellum, several layers with handcraft activities were documented, suggesting a lively occupation inside the fortified area until the 6th century.