Newcastle fort (PONS AELII)
Newcastle was the original eastern terminus of the Wall and yet no fort was built here until the Antonine period, which was probably when the bridge across the Tyne was constructed. The fort is mostly situated underneath the castle but it was originally 0.64ha (1.53 acres) in area. The garrison included the cohors I Ulpia Traiana Cugernorum in the 3rd century and (possibly) cohors I Cornoviorum in the 4th. A stone recording the cohors I Thracum may refer to another garrison from Newcastle, or possibly from an as-yet-undiscovered fort in Gateshead. The fort does not seem to have been attached to the curtain wall (there seem to have been buildings to the north of it) and it was, rather unusually, polygonal in form.
Marked out on that piece of pavement are parts of the headquarters building (principia) and the commanding officer’s house (praetorium). The orientation of these fragments begins to allow an understanding of how the fort sat above the river. There is more to see, however. Head round to the north side of the keep, next to the railway arches, and you’ll see parts of two granaries marked out, one of them partly under the viaduct itself.
The eponymous bridge at Pons Aelii has yet to be located (dendro-chronological dating of timbers supposed to have come from it proved to be medieval) but it must have been situated close to where the Swing Bridge is now located. Recent work in Gateshead has suggested that there may have been a military base there, too (elsewhere in the empire, many bridges over major rivers had military bases at either end).