Belisarius of Constantinople, who arrived in Britain knowing nothing of Isolde’s Menologium, never meant to come to Lindisfarena. After a long journey across the Mediterranean from Greece, his precious books wrapped in pigskin and stacked in sturdy trunks, he had sailed on a Frankish ship from Massilia to the port of Brycgstow. He had come to meet a trader called Theodoric, with whom he had worked many times before, and to deliver his antique books. His sojourn in Britain should have ended where it began, in Brycgstow. And it would have if not for chance - and his own reckless nose for adventure.

After disembarking he had an hour or two to spare before he was due to meet Theodoric, and he wandered through the town.

Brycgstow was a crude place. Built by Germans on no discernible civilised template, the town’s wooden buildings clustered like turds in a cow field and its roads straggled like sheep tracks. The dock area was crowded, and the strand heaped up with goods - no wharves or warehouses here, you just dumped your cargo on the filthy beach. Belisarius kept a sachet of Syrian spices hanging at his neck to keep out the stink of blood and piss and dung, and he tried not to wince when his boots were spattered with filthy mud. On travelling outside the empire he always carried spare shoes.

But Brycgstow greeted ships from all the petty kingdoms of Britain, from Frankia and the northern countries, from the Moors of Iberia and the Goths of Italy, and of course from the East Roman Empire. It was a model of the whole world in miniature, Belisarius thought, as all ports were.

And Brycgstow was famous across Europe as a slave market. The west of Britain was an intersection between the aggressive, squabbling German kingdoms and the older British domains; the endless wars were good for the slave trade. Many of the cowed captives in their pens were Latin-speaking Britons who still thought of themselves as Roman, and would come laden with awkward aspirations. But the various breeds of German were not above selling their own kind when they got the chance. They all looked alike to Belisarius, whose own family were Greeks. He kept few slaves himself; he found slavery distasteful, and he was relieved to stroll away from the dock area, deeper into the town.

He walked through a quarter of manufactories, passing a cobbler’s, an iron worker’s, a silversmith’s. He reached a small market where animals swarmed around stalls piled high with meat and stunted-looking vegetables and fruit. The people were a rough lot, but they seemed healthy enough, tall, many of them blond, and with good teeth. Many wore striking brooches at their shoulders, and necklaces of beads or silver tokens strung across the chest. Men and women alike wore their hair tightly bound up on their heads.