'Thank you, sir.'

'Let the boy out.'

Pertinax hastened to obey and Romulus ducked out of the postern door, which promptly slammed shut behind him.

Mind racing, he walked back, the reply clutched tightly in one hand. Who would have thought he would see inside the domus of the richest noble in Rome? And meet one of Spartacus' original men? Despite the major-domo's scorn, there had been a ring of truth to Pertinax' words.

Romulus couldn't wait to tell Fabiola and Juba. But first he had to get inside Gemellus' gate without the thugs stopping him. He grinned – it was a challenge he would relish.

Near the last crossroads before home, Romulus heard the noise of loud chanting. The street was thronged with even more people than usual and potentially that meant trouble. Keen to get back, he ducked into a narrow alleyway off the main street and worked his way around the junction, the cries of the crowd filling his ears.

'Who wants a trip east?' a man cried.

'Pompey!' came the response.

Romulus paused to listen. It sounded as if Clodius was up to his usual tricks. The leader of the collegia had been on a mission to humiliate Pompey for some time.

'But who should go instead?'

A great roar answered the master rabble-rouser. 'Crassus!'

Romulus kept moving, remembering Gemellus' complaint that tolerating the mobs was just another sign of the Republic's decline.

In the event, distracting the two heavies did not prove at all difficult.

Romulus simply waited until a cart was rolling past Gemellus' house. Using it as cover, he crouched down and ran alongside, leaving the men opposite completely unaware until he was by the door. The boy darted forward and rapped hard with his fist; the pair saw him, cursed and lumbered forward, reaching for their swords. But Juba was waiting and instantly emerged into the sunlight, his blade ready.

Few men in their right minds would take on the Nubian.

They skidded to a halt, leaving Romulus to saunter inside with his friend. He did not linger: delivering Crassus' reply was far more urgent than anything else. Smiling his thanks at the big doorman, he went in search of Gemellus.

The sound of voices carried to him through the tablinum and instinctively Romulus tiptoed across its mosaic floor. From a statue near the open doors, he could hear every word spoken in the garden. The twins had discovered early on that eavesdropping on Gemellus was most informative.

It also taught them plenty about his murky business deals. Although much of what he overheard meant little to him, Romulus took every opportunity to learn more about the world outside the high walls.

The merchant was deep in conversation with his bookkeeper. Servilius was a thin Egyptian with protuberant eyes and receding hair and the only slave Gemellus trusted. Excellent with money, Servilius was despised by the other slaves, who could not understand his unswerving loyalty to his owner.

'Continue.' Gemellus sounded unusually good-humoured.

Servilius cleared his throat. 'My cousin in Alexandria mentioned a possible business venture in his last letter. A very profitable one.' He paused. 'But it would not be without risk, Master.'

'Nothing is these days,' growled the merchant. 'Tell me more.'

'Menes has dealt with a Phoenician bestiarius by the name of Hiero,' Servilius began, 'who proposes to lead an expedition into the deep south, near the headwaters of the Nile. There he will capture all manner of beasts for the arena.'

Romulus could sense Gemellus' interest and craned his head, desperate not to miss a word. The job of the bestiarii was very dangerous and appealed to him immensely.

'Lions, leopards and elephants,' announced the bookkeeper, warming to his task. 'Antelope and unearthly creatures with long necks and legs. The bestiarius even claims he can catch huge armoured monsters with lethal horns on their noses.'

'Is Menes tempted to invest?'

Servilius coughed awkwardly. 'He is providing two-thirds of the financial backing, Master.'

There was no reply for a moment.

'Each one would be worth its weight in gold,' exclaimed Gemellus. The trade in wild animals for gladiatorial contests was fast becoming one of the most lucrative in Rome.

'I thought you might be interested, Master.'

'How much capital is Hiero looking for?'

'For the last third share,' Servilius said, sucking in his breath, 'one hundred and twenty thousand sestertii.'

Romulus' mouth opened. It was more than he could even imagine.

'Fortuna's tits!' cursed Gemellus. 'Where will I get credit like that these days? I'm up to my neck in debt already.'

'Crassus, Master?'

Startled by the name and the nature of Gemellus' dilemma, Romulus jumped. He had had no idea that the merchant was in financial difficulties. It was then that he heard the sound of someone coming down the corridor, probably a kitchen slave with a cool drink for their master. He could not risk being caught, so he squared his shoulders and stepped into the garden, making as much noise as possible.

Gemellus' face darkened further when he saw who it was. Servilius immediately busied himself with his ledger, the giant tome that contained all the merchant's financial details.

'What took you so long?' Gemellus peered at the sundial. 'It's been two hours!'

Not daring to reply, Romulus held out the parchment.

Gemellus scanned it silently. The only noise was the bookkeeper's stylus scratching out figures behind him.

Romulus waited, knowing a beating would follow regardless of what Crassus had written.

Closing his eyes, Gemellus crumpled the note and dropped it to the floor. The rate of interest demanded by Crassus for an extension of his loans was completely extortionate. He did not need that hanging over his head as well.

Full of anger, the merchant beat Romulus harder than usual, but the boy took the punishment without a sound. The unexpected outing and the conversation with Pertinax had been well worth it.

Fabiola watched from behind a bush, biting her lips to avoid crying out at the sight. It would only have earned Romulus an even worse hiding. Her hatred of Gemellus grew day by day. Not only did he rape her mother every night, he regularly beat her brother black and blue. Only the fear of what would happen to her family prevented Fabiola from trying to kill their master.

It was two days before the bruises began to settle and an opportunity arose to confide in Juba. Every time Romulus went to talk to him, someone happened to be present.

Gemellus was ingratiating himself with every banker and moneylender he knew, trying to raise capital for a proposed business venture. Romulus suspected it was to do with Servilius' suggestion. But word must have spread about his huge debts, because visitors came and went, shaking their heads regretfully. The merchant's temper grew even worse. Household slaves crept about, trying not to be noticed. Eventually Gemellus could take no more and stormed off to the Lupanar, his favourite brothel. The bookkeeper was told he would be gone at least a day.

Hearing the master was gone, Romulus ran immediately to Juba, wooden sword in hand. The Nubian listened intently to the story, nodding approval when Spartacus was mentioned. His eyebrows rose with surprise to hear Pertinax had fought with the rebel Thracian.

'I would have joined Spartacus if I'd been old enough,' said Romulus fiercely. He had not been born until a year after the slave uprising ended.

Juba tapped his chest, signifying agreement.

'Show me more moves! I must learn to fight like a gladiator.'

The Nubian smiled and moved into the hallway. Ensuring Romulus was paying attention, Juba turned sideways to present less of a target, holding his sword out just above the waist, shield at chest level. He indicated that Romulus do the same. They stood side by side, repeating the same actions until Juba was happy.