Once she'd finished, Claudia left the arbour and returned to the villa, finding her way back to the library. The librarian was about to lock up, claiming he was looking forward to his lunch of mushroom bread, lentils and barley soup. Nevertheless, he patiently heard Claudia out, then shook his head.

'We have nothing in our library,' he said, 'about medicines, potions or plants, I assure you, mistress.' Claudia made to object.

'You can search if you want,' the librarian declared. He handed her the key. i leave it to you.' 'Claudia, Claudia?'

She turned. Burrus and four of his companions came hurrying across the lawn, their faces dirty and sweat-stained, hair and beards more unkempt than usual. Burrus unhitched his great shaggy cloak, let it fall to the ground and crouched down, peering up at her. i have news,' he gasped.

The librarian slipped away. The Germans had found another wineskin and passed it to each other. Burrus took a mouthful, rinsed his tongue then spat it out.

'I have two messages for you, Claudia.' He stared, blue eyes unsmiling. 'We have been down to the copse. We found no pit, no hole, nothing covered up, but we did find the marks of a cart; that is how they came here, and that's probably how the attackers removed their dead.'

Claudia closed her eyes and beat her fist across her thigh. Of course, the attackers would use a covered cart, pretending to be farmers or merchants, leave the road and, under the cover of the trees, arm themselves and prepare. The same would happen afterwards: the dead would be loaded on to the cart, followed by the masks, armour and swords; in a short while they would be just another covered cart rattling along the busy thoroughfare into Rome.

'And the second message?'

'The Empress is not pleased.'

'I know that!' Claudia snapped.

'She has ordered you to return to Rome immediately to continue your investigation. You are to leave within the hour. You may take your farewell of Murranus, who will stay here. The Empress does not want any distraction for you in Rome.' Burrus delivered the message in clipped, short sentences, then he smiled. 'I am to accompany you. The Empress believes that I will protect you.'

Claudia moved over and patted the huge barbarian on his head. 'I think you are being sent to spy on me, Burrus. To make sure I do what the Empress wants.'

'If the Empress wants it,' Burrus whispered, 'that's how it must be, little one.'

'How soon?'

'We must be gone within the hour.'

Later that day, Claudia sat in Polybius' orchard and watched her uncle, Narcissus, Apuleius and Oceanus finish what had proved to be a delicious meal served by the She Asses' new chef, Celades. Polybius had reluctantly employed the Pict, only to discover he was a real treasure, a skilled practitioner of the culinary arts. Claudia had returned to find the tavern doing a bustling trade, serving a range of cheap dishes cooked by Celades and advertised on a board by Polybius. The local stonemasons, carpenters, tinkers and traders had flocked into the tavern. Now darkness was falling. Claudia had insisted that Celades prepare a sumptuous meal so she could share some news with her uncle and friends. Celades had surpassed himself, serving up hare, hot and spicy, in a sauce stewed from cumin seed, brown ginger, bay leaves and olive oil, followed by ham cooked in a red wine and fennel juice. Poppaoe lit the lamps. Claudia watched her uncle finish off the last of what he called his 'Special Vintage'. He leaned forward, elbows on the table, and grinned at her.

'Well, Claudia, what news do you have for us?'

Claudia looked over her shoulder. Poppaoe, Januaria and the rest were back in the tavern entertaining Burrus, who was telling frightening stories about the monsters, giants and trolls that prowled his northern forests. She turned back. Now was the time.

'The young woman whose corpse was found here, she was certainly not a saint. Presbyter Sylvester has told me that.'

In any other circumstances Claudia would have burst out laughing at the effect of her words. Polybius gaped. Apuleius put his face in his hands. Oceanus nervously thumbed the pickled ear hanging on the cord round his neck. Narcissus the Neat stretched out for his wine cup.

'I don't want to hear any more lies,' Claudia declared. 'I will tell you exactly what Presbyter Sylvester and I have discovered. This morning he gave me a copy of Celsus' De Medicina.' She ignored Apuleius' loud groan. 'Now Celsus talks of many poisons. In fact he made me reflect on a number of things, but one of the subjects he mentions is arsenic, and he describes, in great detail, the death and embalmment of Alexander the Great at Babylon some six hundred years ago. Alexander's body was marvellously preserved, probably due to the arsenic which someone had used to poison him. I am sure the same thing happened to Fulgentia, or whatever her name was. So I want the truth, and I want it now!'

Polybius recovered his wits and opened his mouth, but Claudia looked at him warningly.

'You deserve the truth,' Apuleius began, raising his hands, gesturing at his companions to remain silent, 'and I will tell you the truth. The name of that young woman was Fulvia and she killed herself. Let me give you the details. Years ago my wife and I were sheltering Christians fleeing from the persecutions of Diocletian and Maxentius. Now we all know what happened: families broke up, people wandered the roads, entire families disappeared, children would return home to find parents gone, parents would return to find sons and daughters taken up in the middle of the night. Fulvia was a refugee, an exile from Tarentum. She was passed on by various local Christian churches until she reached Rome.' He sighed. 'To cut a long story short, four years ago we took Fulvia in. She may have proclaimed herself a Christian but she was a thoroughgoing nuisance. She was hysterical, hot-tempered, bitter and constantly critical; her real vocation was to be an actress or a dancer. Everything was a drama for Fulvia. She used to threaten my wife and me with going to the authorities, denouncing Christianity, becoming an apostate. At other times she threatened to kill herself.' Apuleius drew in a deep breath before continuing.

'Now I am an apothecary, a physician. One day I had a confrontation with her, and she became hysterical, screaming and shouting at me. She threatened that she would take some powders, kill herself, and I would be to blame. Of course, I didn't believe her. That same night, in the early hours, I heard sounds from downstairs. I came down. I have a special chamber where I keep potions under lock and key. Fulvia had managed to break in and open one of the coffers. She thought she'd taken some relatively innocuous powder; in fact, she'd mixed too much arsenic with her wine and there was nothing I could do to save her. She eventually slipped into a coma, then death. The marks on her neck and shoulders are due to when I tried to make her vomit or to dilute the poison she'd taken with salted water, even some milk. But as you know,' he smiled bleakly at Claudia, 'if you've read

Celsus, the antidotes for powerful poisons are fairly futile. Fulvia died. I knew what would happen. Already I was under suspicion of being a leading Christian in the local community. If Fulvia's corpse was found in my shop, the Vigiles would come, then the soldiers. I had Christian manuscripts, sacred vessels concealed there. I couldn't afford to risk anything. So I came to my old friend Polybius, who had just taken over the She Asses, and told him what had happened. At the dead of night I moved the corpse here. We washed and cleaned it. I anointed it with a wax-like substance to close the pores of the skin, sealing the powder within, and wrapped the corpse in linen.'

'Arsenic gives off a powder,' Claudia declared. 'I saw traces of it when I first viewed the corpse.'