'My name is Arminia.' I was not in the mood for infants who had been named after heroic enemies of Rome. Arminia and Augustinilla were still egging one another on to see if they could make me charge out of my cage. 'What are you enquiring about in Colonia, please?'

'State secret.' They both went off into shrieks.

'Don't listen to him,' decreed Augustinilla. 'My mother says he couldn't find his own belly button. Everyone in Rome knows Uncle Marcus is a complete fake.'

Looking highly superior they stalked off hand in hand.

'I see they've palled up well,' I commented to Helena. 'Clearly there are no ethnic barriers between horrid little girls. So, we now have not one uncontrollable schoolgirl underfoot, but two.'

'Oh Marcus, don't be such a pessimist.'

Things continued to deteriorate. Helena's brother Justinus arrived at our lodging-house. He would have been a welcome visitor, but he came about a week too soon. He was greeted madly by his little dog, who then ran in and peed on my boot.

Before leaving Justinus at the fort, we had arranged for him to follow us to Colonia, bringing with him the pedlar Dubnus, whom I wanted to use as a guide among the Bructeri. He was only supposed to follow after trying to persuade his legate to release some troops to come across the river with me. Arranging the escort had been expected to delay him. I was startled, therefore, when he burst in on our first evening.

'What's this? Your ship must have rowed the whole distance at double stroke to bring you here so soon! Tribune, I hate surprises. They rarely mean good news.'

Justinus looked sheepish. 'A letter came for Helena. I thought I ought to bring it here as soon as possible.' He handed it over. Both she and I recognised the Palace parchment and seal. Justinus evidently expected her to break the wax eagerly, but she held it on her knee and looked morose. A similar expression was probably afflicting me. 'It caused quite a stir at the fort,' he protested, when he saw her ignoring it.

'Really?' enquired Helena, with her own brand of chilling disdain. 'I keep my correspondence private normally.'

'It's from Titus Caesar!'

'I can see that.'

She was putting on her stubborn face. In kindness to her brother I said, 'Helena has been advising him about a problem with his aged aunt.' She shot me a look that would have skinned a weasel.

'Ah:' Justinus could detect an atmosphere. He had the tact to believe my bitter joke. 'I'd better be off now, Marcus Didius. I need a bathe. We can talk properly another time. I'm staying at the Rhenus fleet fort.'

'Did you manage to get me an escort?'

'You've been assigned a centurion and twenty men. Rather inexperienced, I'm afraid, but it was the best I could do. I told my legate you were official, in fact I invited him to meet you, but if you're undercover for the Palace he prefers to stand aloof and let you get on with it.'

I preferred to stand aloof from this mission myself. 'Old-fashioned, eh?'

'Forays across into the east are not encouraged nowadays.' He meant Rome was in enough trouble in the territory it held, without stirring up the eastern tribes.

'Suits me. I hate formalities. Thank him. I'm grateful for any support. Did you bring the pedlar too?'

'Yes. I warn you, though, he's protesting volubly.'

'Don't worry. I came across Gaul with a chattering barber. I can manage anything after that.'

Justinus kissed his sister and disappeared with alacrity.

We sat apart in silence. In the circumstances I thought it was her turn to speak. Helena generally ignored whatever I thought.

After a moment I muttered, 'I'd kiss you too, but it seems inappropriate with a letter from the Emperor's son lying in your lap.' She made no answer. I wished she would jump up and burn the thing. I remonstrated steadily: 'Helena, you had better open that document.' Refusing would make the tension far worse, so she slowly broke the seal. 'Shall I go out while you read it?'

'No.'

She was a fast reader. Besides, for a love letter it was foolishly brief. She read with an expressionless face, then rerolled it tightly, gripping the scroll in her clenched fist.

'That was quick.'

'More like an order for new boots,' she agreed.

'He's known as a poor public speaker, but a man in his position ought to be able to prime a jobbing poet to scribble a few hexameters to salute a lady: I would.'

'You,' murmured Helena, so quietly it scared me witless, 'would write the hexameters yourself.'

'For you I would.'

She was very still. There was nothing I could do for her.

'It would take me a few thousand lines,' I warbled on miserably. 'You might have to wait a month or two while I polished them properly. If I was asking you to come home to me, I'd want to tell you everything:' I stopped talking. If Titus had offered her the Empire, Helena Justina would be needing to think. She was a cautious girl.

I was trying to convince myself that whatever Titus had to say, it must so far be unofficial. If he was making any serious proposition, their two fathers would be negotiating. Even among emperors- especially among emperors-there are ways these things have to be done.

'Don't worry.' Helena looked up abruptly. It was always the same. Whenever I had reason to be worried about her, she tried to quash it by worrying over me. 'Nothing is going to happen, I promise you.'

'Has the great man asked his question?'

'Marcus, as soon as I reply-'

'Don't,' I said.

'What?'

'Don't reply yet.'

At least if any disaster happened to me, Titus Caesar would look after her. She would never lack anything. And the Empire's gain would be immense. A Caesar who reigned in partnership with Helena Justina might work incomparable deeds. Titus knew that. So did I.

I ought to set her free. Some people might say that once I reached Germania Libera I had a real duty to vanish in the woods. In the whimsical moments when I cared about Rome, I even thought that myself.

She was strange. Instead of demanding what I meant, she rose, came across to me, and then sat in silence beside me, holding my hand. Her eyes brimmed with tears she was too stubborn to shed.

She knew, of course. I wanted her myself. Even while I was crossing the Styx in Hades, I would be squabbling with the ferryman and trying to fight my way back off the boat to return to Helena. I only wanted to safeguard her future in case I would not be there.

She knew the rest, too. Going across the river would be stupidly dangerous. History was against me. The free tribes were implacable enemies of everything Roman. And I knew from Britain how the Celts treated their enemies. If I was captured I could expect to be denied diplomatic immunity. My skull would be speared up in a niche outside a temple. What happened to the rest of me before they swiped my head off was likely to be more degrading and more painful than I could bear to contemplate. I did not ask how much Helena knew of all this, but she was well read.

When I fell for Helena Justina, I had vowed I would never expose myself to serious risk again. There had been plenty of tricky exploits in my past, most of which I would never even hint at to her. But a man grows older. He learns that other things matter. She could guess I had a horrific career behind me, but she believed that telling her I loved her meant my daredevil days were over. Nobody could blame the girl; I had made the same assumption myself.

Now I looked like one of those madmen for whom danger is an addiction. Helena's plight seemed as bleak as if she had shackled herself to a drunkard or a fornicator. She must have told herself everything would change under her influence, but now she saw it never could: Still, I knew I was different. This was just one last attempt to acquire a decent bounty from the Emperor, all so that I could win her.