It was well maintained inside, and dry, and all he had to do was follow it until he saw light at its other end. He approached it cautiously, and as he did so Caterina’s voice came to him again. The tunnel ended in a short flight of stone steps which led up into a back room on the ground floor of one of the western towers of Forlì. It was deserted, Caterina had collected quite a crowd. Through a window he could see most of the Orsi troops’ backs, as they watched, and even occasionally applauded, Caterina’s performance.

‘... if I were a man I’d wipe those grins off your faces! But don’t think I won’t give it my best shot anyway. Don’t be misled by the fact that I’ve got tits -‘ A thought struck her. ‘I bet you’d like to see them, wouldn’t you? I bet you wish you could touch them, lick them, give ’em a squeeze! Well, why don’t you come down here and try? I’d kick your balls so hard they’d fly out through your nostrils! Luridi branco di cani bastardi! You’d better pack up and go home while you still can – if you don’t want to be impaled and stuck up all along my citadel walls! Ah! But maybe I’m wrong! Maybe you’d actually enjoy having a long oaken pole up your arses! You disgust me – I even begin to wonder if you’re worth the bother. I’ve never seen such a piss-poor shower of shite. Che vista penosa! I can’t see that it’d make much difference to you as men even if I had you castrated.’

By now Ezio was in the street. He could see the gate closest to where Caterina and Machiavelli were located. At the top of its arch a bowman stood by the heavy lever which operated it. Moving as silently and as quickly as he could, he shinned up to the top of the arch and stabbed the soldier once in the neck, dispatching him instantly. Then he threw all his weight on to the lever, and the gates below swung open with a mighty groan.

Machiavelli had been watching carefully all this time, and as soon as he saw the gates opening, he leant over and spoke softly to Caterina, who immediately spurred her horse forward at a frantic gallop, closely followed by Machiavelli and the rest of her entourage. As soon as they saw what was happening, the Orsi troops on the ramparts let out a yell of anger and started to swarm down to intercept, but the Sforza faction was too quick for them. Ezio seized the bow and arrows from the dead guard and used them to fell three Orsi men before he swiftly climbed a nearby wall and started to run over the city’s rooftops, keeping pace with Caterina and her group as they rode through the narrow streets towards the citadel.

The deeper they went into the city, the greater was the confusion that reigned. It was clear that the battle for control of Forlì was far from over, as knots of soldiers under the banner of the blue snakes and black eagles of the Sforza fought the Orsi mercenaries, as ordinary citizens rushed for shelter in their houses or simply ran aimlessly hither and yon in the confusion. Market-stalls were overturned, chickens ran squawking underfoot, a small child sat in the mud and bawled for its mother, who ran out and snatched it to safety; and all around the noise of battle roared. Ezio, leaping from roof to roof, could see something of the lie of the land from his vantage-point, and used his arrows with deadly accuracy to protect Caterina and Machiavelli whenever Orsi guards got too close to them.

At last, they arrived in a broad piazza in front of the citadel. It was empty, and the streets leading off it appeared deserted. Ezio descended and rejoined his people. There was nobody on the citadel’s battlements, and its massive gate was firmly closed. It looked every bit as impregnable as Caterina had said it was.

She looked up, and cried: ‘Open up, you bloody parcel of fools! It’s me! La Duchessa! Get your arses in gear!’

Now some of her men in the citadel did appear above them, among them a captain who said, ‘Subito, Altezza!’ and issued orders to three men who disappeared immediately to open the gate. But at that instant, howling for blood, dozens of Orsi troops poured from the surrounding streets into the square, blocking any retreat and pinning Caterina’s company between them and the unforgiving wall of the citadel.

‘Bloody ambush!’ shouted Machiavelli, with Ezio rallying their own handful of men, and keeping between Caterina and their enemies.

‘Aprite la porta! Aprite!‘ yelled Caterina. And at last the mighty gates swung open. Sforza guards rushed out to aid them, and, slashing at the Orsi in vicious hand-to-hand fighting, beat a retreat back through the gates, which quickly slammed shut behind them. Ezio and Machiavelli (who had quickly dismounted) both leaned against the wall, side by side and breathing hard. They could scarcely believe that they had made it. Caterina dismounted too, but didn’t rest for an instant. Instead she ran across the inner courtyard to a doorway in which two little boys and a wet-nurse holding a baby were waiting fearfully.

The children ran to her and she embraced them, greeting them by name, ‘Cesare, Giovanni – no preoccuparvi.’ She stroked the baby’s head, cooing, ‘Salute, Galeazzo.’ Then she looked around, and at the wet-nurse.

‘Nezetta! Where are Bianca and Ottaviano?’

‘Forgive me, my lady. They were playing outside when the attack began and we haven’t been able to find them since.’

Caterina, looking frightened, was about to reply when suddenly a huge roar went up from the Orsi troops outside the citadel. The Sforza captain came rushing up to Ezio and Machiavelli. ‘They’re bringing in reinforcements from the mountains,’ he reported. ‘I don’t know how long we’ll be able to hold out.’ He turned to a lieutenant. ‘To the battlements! Man the cannon!’

The lieutenant rushed off to organize gun-crews, and these were hurrying to their positions when a hail of arrows fired by Orsi archers started to descend on the inner courtyard and the ramparts above. Caterina hustled her younger children to safety, shouting to Ezio at the same time, ‘Look after the cannon! They’re our only hope! Don’t let those bastards breach the citadel!’

‘Come!’ shouted Machiavelli. Ezio followed him up to where the cannon were ranged.

Several of the gun-crews were dead, along with the captain and the lieutenant. Others were wounded. The survivors were struggling to trim and angle the heavy cannon to bring them to bear on the Orsi men in the square below. Huge numbers of reinforcements had come up, and Ezio could see that they were manhandling siege-engines and catapults through the streets. Meanwhile, directly below, a contingent of Orsi troops were bringing up a battering-ram. If he and Machiavelli didn’t think of something quickly there would be no chance of saving the citadel, but to withstand this new assault he would have to fire the cannon at targets within the walls of Forlì itself, and so risk injuring or even killing some of its innocent citizens. Leaving Machiavelli to organize the gunners, he raced down to the courtyard and sought out Caterina.