Mario cut one guard down just as he was about to stab Ezio from behind with his spear.

‘Not bad for an old man,’ Ezio cried gratefully.

‘I expect you to return the favour,’ returned his uncle. ‘And not so much of your “old man”!’

‘I haven’t forgotten everything you taught me.’

‘I should hope not. Look out!’ Ezio whirled round just in time to slice the legs of a horse from under a guard who’d galloped up wielding a vicious-looking mace.

‘Buona questa!’ shouted Mario. ‘Good one!’

Ezio leapt sideways, avoiding two more of his pursuers and managing to unsaddle them as they careered past, carried forward by their own momentum. Mario, heavier and older, preferred to stand his ground and cut at his enemies before leaping out of their reach. But once they had gained the edge of the broad square that faced the great cathedral church of St Peter, the two Assassins quickly clambered to the safety of the rooftops, scaling the crumbling house walls as nimbly as geckos, and scampering across them, leaping over the gaps where the streets between them made canyons. It wasn’t always easy, and at one point Mario nearly didn’t make it, his fingers scrabbling for the gutters as he fell just short. Panting hard, Ezio doubled back to pull him clear, succeeding just as the crossbow bolts fired by their pursuers rattled uselessly past them into the sky.

But their going was far faster than that of the guards, who, more heavily armoured and lacking the skills of the Assassins, tried in vain to keep up by running though the pathways beneath until gradually they fell back.

Mario and Ezio clattered to a halt on a roof overlooking a small square on the edge of Trastevere. Two large, tough-looking chestnut horses were saddled and ready outside a lowly-looking inn, its battered sign declaring it to be The Sleeping Fox, while being watched over by a wall-eyed hunchback with a bushy moustache.