Wild cheering erupted; many of the women screamed and threw flowers.

'We are here because of the generosity of one person . . .' The speaker paused, allowing the noise to build. 'I give you – the conqueror of Mithridates, Lion of Pontus. The victor over the Cilician pirates. The builder of the people's theatre. Today's editor – the great general – Pompey Magnus!'

As if ordered to do so, sunlight streamed from a break in the clouds. Roars of approval rose into the air and Romulus realised that the two groups had been encouraged to stand so they formed a corridor. Beams shone from the west across the arena, between the fighters.

Lighting up Pompey, the sponsor.

'Just a big show,' he muttered to Brennus.

'Politics. If the people love the games, they support their sponsors. That gives him power.'

'We are fighting for a damn politician?' Romulus had not thought to question the reason behind fights. The citizens of Rome adored bloodshed, but it was not they who actually held the contests. It was those in power who were responsible – the senators and equestrians. The gladiators were just puppets on strings.

Used to it all, Brennus nodded.

Romulus was outraged. 'Lots of us are about to die. Why?'

'We are slaves, Romulus,' he said simply.

An image of Crassus' doorman came to him. 'Says who?' Romulus countered. 'That prick?' He pointed at the nobles' box.

'Shut up!' Brennus looked over both shoulders. 'Memor would execute you on the spot if he heard that.'

'It's been done before,' argued Romulus passionately. 'Imagine what fifty of us could do to the bastards up there.'

'Rebellion?' The Gaul whispered the word.

'Claiming freedom, more like.'

'Pompey Magnus!' cried the master of ceremonies again.

'Time to fight.' Brennus winked. 'We 'll talk later.'

The crowd cheered dutifully while Pompey acknowledged their adulation with a languid wave. A middle-aged man with white hair, prominent eyes and a bulbous nose, he surveyed the fighters keenly.

'Salute Pompey Magnus!'

'We who are about to die, salute you!' The gladiator's vow roared from a hundred throats.

Pompey nodded with more respect than he had given the audience.

'At least he is a warrior,' said Brennus. 'Not like that dog Crassus, who never stops telling everyone what a great general he is.'

'Pompey is paying for us to die,' hissed Romulus. 'Fuck him!'

The Gaul seemed startled, but a light Romulus had not seen before stirred in his eyes.

'Die like men!' Pompey addressed the combatants. 'Show courage. Those who survive unhurt will be well rewarded. Begin!'

There was silence for a few moments as the fighters watched each other, bodies stiff with tension.

Romulus was filled with excitement at the Gaul's response to his comment. But everything would have to wait until the combat was over. If they survived. He turned round. Figulus and Gallus were some distance away, pretending not to look in their direction.

'Stay close. Watch your backs!' Brennus shouted, gripping his sword in a huge fist. 'Move it! Don't let them come to us!' he yelled at the retiarii.

The fishermen shuffled forwards, holding their weighted nets low, ready to throw. Dacicus fighters fanned out in response, beginning to advance. Romulus stood three steps to Brennus' right, shield high, dagger in hand. The standoff with the guards had given him an idea.

'Once the retiarii are occupied, I want a charge through the centre.' Brennus spoke in a low voice so that only those nearby could hear. 'Ignore normal combat rules. Kill quickly and move on.'

'We 're with you, Brennus,' said a Thracian.

The others muttered agreement. Brennus looked at each of them, nodding grimly.

Moments later, the fight began as Magnus retiarii reached the first Dacicus gladiators. Nets twirled and spun through the air, men dodged and cursed, skidding on the hot sand. Romulus saw a trident piercing an enemy's throat, tearing flesh apart in a crimson spray of blood. Fighters circled each other, weaving and thrusting in lethal, mesmerising dances.

The main body of the enemy had been unprepared for the sudden attack. Apparently leaderless, the intimidated Dacicus gladiators were at a loss how to respond.

The moment was ripe.

'On me!' Brennus roared, lifting his longsword and loping through the individual combats in front.

Thirty men followed, weapons at the ready.

Romulus kept pace with the Gaul, eyes peeled. As he passed a fight between a Magnus fisherman and a Samnite, he took a chance. The heavily armed warrior had lowered his oblong shield for a moment, watching the retiarius balance the net to throw. Romulus leaned forward on one foot, cocking his right arm back. Taking aim, he swung forward, releasing the knife. It flew straight and true, cutting deep into the unsuspecting Samnite 's throat, below the visored helmet. The man made a choking noise and dropped both sword and scutum. Blood poured around his clutching fingers as he slumped to the sand.

The retiarius turned to see who had felled his opponent.

With surprise, Romulus recognised Gallus.

'Bastard!' The retiarius' face twisted with anger. 'You're dead meat.'

Gallus' violent reaction shocked him and proved that the threat from the disgruntled fighters was very real. But his enemy had no time to react as a heavily built secutor lunged in for the kill.

'Got one already!' Romulus pulled his sword free as he raced to catch the Gaul.

'How?'

'With my dagger!'

'Good work! Pick up another if possible. Never know when you might need it!' Brennus smiled and increased his speed, outstripping the others.

Brennus' charge was awe-inspiring. With a roar that simply froze the first Dacicus fighter on the spot, the Gaul smashed down on to his bronze helmet with the longsword, crushing the skull.

The Thracian crashed to the ground.

Brennus stepped over the body, swept the next gladiator's shield out of the way with his own and stabbed him in the chest from close range. He roared a deafening battle-cry that echoed round the enclosure.

A few moments passed. Unsure what to do, the Dacicus fighters stood transfixed by the fearsome apparition.

The Gaul dispatched a secutor with ease. 'Come on!' Romulus shouted as he ran forward, pressing home the advantage. 'Ludus Magnus!' An inarticulate bellow of pent-up rage and fear answered. With a crash of swords on shields, the Magnus gladiators ran at their bewildered enemies.

Romulus found himself facing a murmillo only slightly larger than he. His opponent swung a heavy overhand blow, trying to hammer through with sheer force. Romulus parried with relative ease, keeping the shield high. He drove forward under the other's gladius, staring at his enemy from a few inches away. The gladiator's mouth opened, knowing what was about to happen.

Romulus plunged his sword into the man's exposed midriff.

The murmillo screamed and folded over in agony. Swiftly Romulus withdrew the blade, letting him fall to the sand. A huge blow downwards with the shield's sharp edge sliced open his neck. Sure the fighter was critically injured, Romulus stepped away.

Cotta had taught him the old-fashioned methods of gladiator combat. In this way, formal fights could last for hours, impressing the crowd with the skill and swordsmanship of the participants. But in the situation Romulus was in right now, there was no point in showing off. Although more brutal, it was better to follow Brennus' method by incapacitating or killing as fast as possible.

Brennus was ten steps away to the left, hacking a Thracian to pieces while fending off a second with side-sweeps of his longsword. On the right, Magnus men were head to head with enemy murmillones and dimachaeri. One figure with two swords was particularly skilled. Romulus watched in amazement as he spun like a dancer, maiming and killing at leisure. The end came when a Magnus retiarius smothered him from behind in his net. As the dimachaerus tried to struggle free, several gladiators swarmed in, spitting him like a wild boar.