A week after Thalius’s own arrival at Banna, Constantine and his entourage arrived - or some of them; many had stayed behind at Eburacum.

Constantine immediately ordered a review of the fort’s troops. This took place on a bright, fresh morning, and Thalius and his companions watched from the comfort of a pavilion as guests of Cornelius.

The soldiers in their centuries drew up in good order outside the fort walls. The centuries’ standard-bearers held aloft the emblems of their units, and each held a labarum. A new military standard said to be of Constantine’s own devising, this was a long spear covered in gold, with a transverse bar to give it the shape of the Christian cross. At the summit of the cross was a wreath of gold and precious stones, containing a finely worked chi-rho Christogram.

The troops made a respectable sight, even though Thalius could see their armour and weaponry were scuffed and much repaired - it was said that some of these bits of kit had been handed down from father to son for generations. Not only that, in the light of day the walls of the fort itself looked frankly dilapidated. The fort and its units had been here for centuries, slowly subsiding into the cold northern mud, while the boundary between the soldiers and the civilian population from which they were recruited grew ever more blurred.

One of Constantine’s projects was to cement reforms of the army begun under Diocletian, reforms which reflected the military reality of the age. The old distinction between legions and auxiliary units was abandoned. Now the army was divided between a mobile field force, and static units of border troops, like the units here at Banna. There was a new military hierarchy, of dukes and counts - like the Duke of the Britains stationed at Eburacum, and a Count of the Saxon Shore who controlled coastal forts like Rutupiae. Once the governors had been commanders-in-chief of their provinces’ armies, but now the dukes and counts were independent of the governors - indeed their remit generally spanned more than one province. This was another example of the emperors’ continuing strategy to fragment power and so limit the challenge of any one rival.

Thalius understood the military logic, he believed. You held off the barbarians at the border, and if they did get through you allowed them to penetrate deep into a fortified country, while bringing your mobile forces to bear. Even the walled towns were a part of the system, in a sense. But it was in the nature of stasis to decay, and frontier units like this tended to lose their shape and discipline. Thalius had heard lurid rumours of corruption, of commanding officers drawing pay for long-dead soldiers. It was just as well that the Emperor had come by to give the place a sprucing-up.