Brigonius reached the headquarters building. He crossed the broad cloistered courtyard with its well, heading for the central cross-hall, the basilica. These two areas were large enough to hold all the troops in the fort. To the rear of the basilica was a row of offices, at the centre of which was the shrine, the aedes, with its statue of Hadrian, the standards of the fort units, and other religious tokens. Two rooms to either side were the offices of the adjutant, the cornicularius, and of the signiferi, the standard-bearers. The shrine and offices had open fronts with low ironwork screens. This little area was the fort’s heart. The signiferi were responsible for the crucial issues of the soldiers’ pay and savings, and behind the shrine itself was a strongroom containing the fort’s cash. Brigonius had watched this being built from the ground up, and indeed had sold the Romans much of the stone they had needed. It was all still so new he could smell the mustiness of fresh plaster.

And today, in the basilica, the fort commander was holding a reception for Sabinus’s party. There was little left of the pretty-boy tribune about Sabinus; he had become a tough-looking man of his world, competent and corpulent.

Sabinus was leading this delegation from Rome, representing both the senate and the Emperor’s household. It was here to make a regular inspection of the Wall and the situation in the north in general - and, so the rumours went, to deal with a spot of unpleasantness concerning the conduct of Claudia Severa. Brigonius was surprised that Sabinus should have been put in charge of a problem concerning his own mother-in-law. But perhaps this subtle cruelty was characteristic of Rome these days, ruled over by an ageing, detached and increasingly capricious Hadrian.

As if to symbolise the complicated unpleasantness of the imperial court, among the Emperor’s representatives was Primigenius. The freedman looked as sharp and wily as ever. But, stick-thin, his head shaven and his sunken face laden with cosmetics, he had not aged well, his beauty long lost. Brigonius was actually introduced to the man, but Primigenius didn’t show a flicker of recognition.

And here, of course, was Lepidina with her glowering husband. She looked her age - she was thirty-four now - but she was still heartbreakingly beautiful. Through his sparse correspondence with Severa, Brigonius had been aware of Lepidina’s marriage to the Roman. But still he was somehow shocked as, for the first time, he saw Lepidina on the arm of Sabinus. Brigonius understood from whispers that Sabinus’s career hadn’t progressed quite as well as he had once planned. Perhaps that explained the darkness around his eyes, the lines around a down-turned, rather cruel mouth, and an air of patient wistfulness Brigonius sensed about Lepidina.