a bath-house and the basilica in the middle of the 3rd century. Around this time it seems to have been garrisoned by the ala Sebosiana and the numerus Barcariorum Tigrisiensium. Around 330 AD the fort underwent a drastic remodelling in a style similar to the Saxon Shore Forts. On the northern side, an approximately thick wall with polygonal external bastions, was constructed in a south westerly direction, over the remains of the earlier forts. The only surviving ruined wall of the 4th-century fort, identified as part of the fort in 1950, is now known as Wery Wall. It is thought to be the core of the external bastion at the northern angle of the wall's circuit and was likely topped with a heavy artillery piece. In the 18th century, a fragment of the south wall was recorded, noticeably not parallel to the north, but thought to belong this fort, suggesting it did not follow the classic Roman plan. Next to the Wery Wall (near the junction of Bridge Lane and Church Street), the remains of a bath-house incorporating a reused inscription of the Gallic Emperor Postumus, dating from 262–266 AD, were discovered in 1812. In the 1950s it was still thought to be contemporary with the 4th-century fort. However it has since been found to have been associated with a large courtyard building, possibly an important residence or maybe a 'mansio' within the vicus area, demolished to make way for the 4th-century construction. The fort underwent a few more extensions, and at its largest area it was . The evidence suggests that the fort remained active up to the end of Roman occupation of Britain in the early 5th century. The later fort is the only known example of this type in northwest Britain. Little is known of the history of the fort afterwards, until the founding of the Benedictine priory (along with Lancaster Castle it is supposed) by Roger de Poitou in 1094. A Saxon monastery was probably built on the site during the sixth century until it was demolished and replaced by the Benedictine priory in 1094. The area is a protected Scheduled Ancient Monument. The Wery Wall is also a Grade II listed building. See also Over Burrow Roman Fort, another fort in Lancaster district Listed buildings in Lancaster, Lancashire Scheduled monuments in Lancashire References Bibliography Buildings and structures in Roman Britain Roman fortifications in England Roman