Next day began with a visit to my father at the Saepta Julia. My runner, Gaius, had failed to report back, but I found him with Pa at the family antiques warehouse. Gaius had completely forgotten about my questions, and was absorbed in negotiations to sell Pa various statuettes he had stolen from temples when I took him on our tour of Greece. Pa was in his usual battered old folding campaign chair; Gaius was lounging like a prince in a stationary litter that had a five-foot-high gilded armchair. Most of the carrying poles looked sound, but the chair was very worn. 'He's got a good eye,' beamed my father approvingly. 'Oh he knows when to commit sacrilege. Gaius is a little tyke; he could have got us all arrested if anyone had noticed him looting ritual offerings.' Luckily, in the family tradition, Gaius could bluff his way out of trouble. He was around sixteen, with a curly rug of black hair just like my father's (and mine), and currently had the air of one born to sprawl under a regal canopy as if being carried to his banker's by a team of eight Mauretanian bearers. 'Now look here, Father, I sent this chancer to you with some important questions -'

'No, just look at this -' Pa held up a tiny model of a womb. Some patient cured of a tumour or infertility had donated it gratefully to the gods at Olympia, Corinth or Athens, only to have Gaius swan along and swipe it. 'This is quite a rarity.' Pa noticed Gaius taking too much interest, so dropped the praise before my nephew tried to negotiate an improved purchase price. 'Difficult to sell because of the religious connection…' Gaius raised his eyes to the ceiling; he recognised devious backtracking. 'Uncle Marcus will vouch for the provenance.' 'No, I'll vouch for you being a bad boy who has no respect for ancient sites, Gaius!'

'Don't be so stiff-necked,' ordered Pa. 'Give the lad a bit of encouragement. He's shaping up really nicely; I need Gaius, since you refuse to take an interest in the family business.' Groaning, I managed to extract from my father a description of the silver ear-rings Justinus had bought to mollify Claudia. I told Pa to look out for Justinus, the ear-rings, or a lost-looking woman of German extraction whose name I was not allowed to mention. 'Oh you mean Veleda? Everyone is talking about her being free,' said Pa.

'Is there a finder's fee?' Gaius demanded, voicing what my father would have put to me had he got in first. Instead, Pa, ever the hypocrite, pretended to tut at the greed of modem youth. 'The reward is a clear conscience.' 'Not enough!' snorted Pa, and Gaius nodded. 'Doing your duty to preserve the Empire -' 'Bugger that for a game of soldiers,' sneered Gaius. This time Pa did the seconding. Not long afterwards I was in the Emporium, trying to track down German traders. The Emporium was the long stone building on the banks of the Tiber, which ran from near my present house southwards along the shipping lane, almost to the city boundary. There were unloaded all the best commodities, brought in from worldwide sources, to be sold in Rome. It was a wondrous hubbub of sights, sounds and smells, where tight knots of dealers and double-dealers fixed the rates and the outlets for artwork and marble, precious woods and metals, spices, gemstones, wines, oils, dyes, ivory, fish products, leather, wools and silks. You could buy a barrel of fresh British oysters in saline for your dinner party, peacock fans to decorate the dining room while you ate them, a handsome slave to serve the meal, and a sarcophagus to hold your corpse after you discovered the oysters had not survived the journey safely. The item prices were tempting – until you added in the dealers' premiums, luxury tax and the costs of transport to your house. This was if you managed to get in and out of the building without having your purse stolen.

My father, in whom snobbery flared high, had declared there would be no importers bringing local wares from either Roman or Free Germany, though I would find plenty of exporters sending fine Roman products to deprived provincials. He was only slightly wrong. Following his directions, I did track down a few sad purveyors of Rhenish hides, woollen coats, and even decorated terracotta bowls, but most of the negotiators who were here from the north were sending luxuries back home. Where they were selling, their dinnerware was good (Helena and I already owned a similar set from Gaul), but as they were passing off the stuff as coming from the well-known factory sites at Arretium, the prices here were Italian and there was no cost benefit.

The men I interviewed wore heavy trousers and tunics, with cloaks fastened on one or both shoulders. Some had brooches in intricately twined Celtic patterns; others fixed their garments with fibulae whose gold filigree was much more Mediterranean, and occasionally ancient. They had been trading with Rome for generations – and probably trading with Greece long before that – whereas they had been trading in the city here for maybe only thirty years, since the Emperor Claudius introduced German allies into the Senate and, while fighting the prejudice of his peers, tried to welcome tribal leaders to Rome and Roman society. This group were mean-eyed capitalists from the west bank of the Rhenus who did not want peace on the east bank because it posed a direct threat to them financially. Theirs was the usual self-serving of commerce. They wanted to remain sole suppliers of Roman goods to their own area. Sharing the trade with Easterners did not appeal. They were very quick to label the east-bank tribes as barbarians.

I probed delicately how they had felt about Veleda. I was chancing it here. Rebellion was a sensitive subject in Europe. Even on the western bank, which had been in Roman control for a long time, there were those who had sought independence not so long ago when they thought Rome was vulnerable. But if these men had felt any sympathy with Veleda back then, they knew better than to show it now.

Laeta's injunction to secrecy made it impossible to ask whether they would help Veleda if she came to them as a supplicant. I could see a risk that her well-known hostility to Rome might arouse anti-German feeling generally, if the public heard she was in our city. If that happened, maybe the traders would turn against her for causing them problems. Insofar as they would talk about her, they claimed that Veleda had always denounced them as collaborators and they denied that there had ever been any possibility of an alliance across the river.

This was bosh. I knew that before Vespasian stabilised the region recently, there had been contact, of which some was very violent but much was friendly. I did not trust the traders, therefore; and since they obviously wondered why I was questioning them, it was fair to say they did not trust me.

I got nowhere. Since I had to disguise my purpose, I had expected nothing better. I did obtain one useful piece of information: how to find a particular group of Germans who had lived in Rome for decades. The traders sent me to them with sardonic expressions – and I knew why. They were hoping their notorious fellow-countrymen would do me physical damage. In fact, they probably thought I was about to be bent into a mystical Celtic knot with all my protruding bits neatly tucked in. The group I went visiting had shrunk to a grim little enclave: I had tracked down the neglected remnants of Nero's legendary German bodyguard.

I was among elderly men giving off a strong odour of the dangerous past. Those were sour times, and these were sprawling old bullies, nostalgic for a culture that no longer existed. Why had they remained in Rome? Probably to avoid disappointment if they returned to their own land and discovered that it was now populated by neat Roman towns where citizens carried out Romanised occupations in a Roman ethos. Even the fanners and country manufacturers brought in their produce to sell at our kind of market in our style of urban forum. Across Europe, fewer and fewer people lived in roundhouses. Tribal culture was dying. Upper and Lower Gennany were filled with industries making equipment for the legions. Beer was losing out; vineyards were spreading ever northward.