The Roman fortess at Eboracum occupies a site on the northern bank of the River Ouse with the principia located directly under the minster. What is apparent is that the south west wall is constructed significantly differently to the remaining three walls and I just want to explore this a little more.
The multangular tower. The front left corner of the York fortress probably rebuilt by Constantine I in the early third century AD. The later Mediaeval brickwork in larger stone is clearly evident to the top of the tower.
One of the most recognisable features that sets this wall apart are the two "multangular" towers with 10 facets (14 if they were to be constructed to join up) that sit at the extreme ends, only one of which is still visible, located in the Museum Gardens of the Yorkshire museum. The external nature of these two corner towers is unusual, although not unknown, and it has been postulated that because similar towers are found at Gamzigrad in Dacia, the location of the palace of Galerius, where construction began at the beginning of the fourth century.
The interior of the multangular tower with the holes visible in the wall for the false floor and late Roman stone sarcophagi in the base.
Another feature of this south east wall, not reproduced on the other three walls of the York fortress, are the external butresses to the interval towers. This method of construction is known from Britain on the Roman forts known as the Saxon shore forts, although those do not posess the distinctive corner towers observed at York. Numismatic evidence dates the Saxon shore forts to be constructed from late in the third century through to the first couple of dacades of the fourth.
The small stonework and upper brick layer of an external tower on the front of the Roman fort at York dating from the fourth century AD.
So, on the face of it there does seem to be justification, in the absence of other evidence, for an early fourth century date for the construction of this particular wall, if no a reworking of all four walls at York.
One question that is hard to answer is why only undertake this work on one wall of the fort? A cynic might say that it was purely for appearences, the look was more important than the substance. This wall certainly houses the Porta Praetoria, the gate that was the main entry into the city and prestige could be an option.
It also faces a structure on the oppisite bank of the river that was the residence of the Governor of Britannia Inferior (the fourth century division of Roman Britain into "Superior" and "Inferior" is well documented).
Finally, could it be the result of an imperial presence "gentrifying" or "grandifying" the entrance? Constantius Chlorus (AD 305-6) was resident in York when he died, along with his son Constantine ("the Great"). The death of Constantius precipitated Constantine being proclaimed emperor by the troops. We also have the possibility that it was done for a potential subsequent visit of Constantine to York around the time of his quinquennalia or 5th anniversary of his accession.
Constantine spent his quinquennial year (July 310-July 311) in the western provinces. The Latin panegyrics note a visit to Autun possibly just after July 211 and no other visits listed BUT Eusebius, in Book 1 of his "Life of Constantine", does have a passage of interest:
"Having disposed of these affairs to his satisfaction, he directed his attention to other quarters of the world, and first passed over to the British nations, which lie in the very bosom of the ocean. These he reduced to submission, and then proceeded to consider the state of the remaining portions of the empire, that he might be ready to tender his aid wherever circumstances might require it."
The passage, coming just before the passages dealing with the war against Maxentius that concluded with the battle of the Milvian Bridge in 312, would apparently date his British caampaign to 310/11, a visit that would coincide also with the quinquennalia and one might find it reasonable to propose an imperial visit at this celebratory time to the place of elevation which, in itself, could have brought about the cosmetic improvement to the fortress.