Nelo forced himself to calm down. This was just some old doctor his mother had known at the Wall. He opened his arms and handed over the sheaf of drawings.

Ontin flicked through them. ‘Very vivid. Not that I know anything about art.’ He turned around one image of an amputation, the doctors and their slaves holding down a writhing man. ‘You’ve even got the details of the instruments right. You should be proud of this, not hiding it in the dark.’

Nelo took his pictures back. ‘There are lads in my barracks who would wipe their arses with them. Or wipe my arse.’

Ontin stared, and laughed. ‘Well. I suppose an army isn’t the place for a budding artist. You mustn’t let them grind you down, you know. Reduce you, as you crush your grain on the quern. Remember who you are, Nelo. You are a Northlander. And you always will be—’

‘What do you want?’

Ontin was nonplussed. ‘Ah. So, to business.’ He looked oddly regretful. ‘I have something for you.’ He opened his leather pouch. ‘Do you know a man called Pyxeas?’

The name came out of a mist of memory. ‘He’s my uncle. Or maybe he’s my mother’s uncle. He’s the one my mother took to Hantilios.’

‘One of our greatest minds, my boy. I mean Northland’s. In this or any age. He’s far from home too. Well, he, or rather one of his students, gave me letters to bring to your family, if and when I got to Carthage.’ He dug a packet of papers out of his pouch, and glanced around before handing them to Nelo. ‘Taken me a rather long time to deliver it, I admit, but it hasn’t been too easy to find you, boy – and I can’t track down your mother and sister at all. But I’ve had fair copies made, for your mother and sister when I find them, and other exiles from home. Best not to tell anybody about this, I mean nobody outside the family. Something of a Northland secret, or it has been so far.’

Nelo opened the papers and scanned the neat writing. It was boldly addressed ‘To My Family’, and signed as ‘On Behalf Of Your Loving Pyxeas, May the Blessed Mothers Protect You In Your Exile.’ The rest of it was densely written in long convoluted sentences. There were no headings, no summaries – no pictures, which Nelo would have fallen on immediately. He was aware that Ontin was watching him. He picked out a few words: ‘ “Hazel or alder or willow . . . sulphur from the volcanic pools of Kirikland . . . scrapings from the urine-soaked floors of barns and latrines . . .” Latrines?’

‘That’s where you collect the solve stone. And the wood types are the best kind for making the charcoal that’s needed.’

‘Needed for what?’