Marcus did not dare reply, having made his point, and Caesar turned away and called for a groom to bring his horse.

The snow continued to fall through the morning as the horsemen followed the track, often in single file to negotiate the drifts that had formed. On either side the boughs of the pine trees were heavily laden and the dull thrumming of the horses’ hoofs was muffled as they rode on. Then, at noon, shortly after the snow had stopped falling, the track descended into a small valley and there was a cry from one of the men scouting ahead. Marcus and the others looked up expectantly as a rider galloped back along the road. He reined in sharply and snow sprayed into the air as he thrust an arm out.

‘There’s a fire ahead, sir!’

‘A fire?’ Caesar grasped his reins tightly. ‘Then we may have them! Let’s go!’

He spurred his horse forward and the rest of the column rippled into motion, horses thundering along the track, their steamy breaths whipped out from flaring nostrils. All thought of the cold disappeared from Marcus’s mind as he urged his mount to keep up with Caesar and Festus. The rest of the bodyguard and staff officers galloped behind, followed by the cavalry.

Ahead, the other scouts were waiting on a small rise that afforded a view along the valley. As they crested the ridge, Marcus saw that the trees fell away on either side, with open land ahead, nestling between the mountains. Aged walled enclosures showed that the land had been used as pasture for many years. A stream meandered along the valley floor into a small lake and ahead, beside a mill, stood a collection of farm buildings enclosed by a wooden stockade. Bright flames licked up from the windows in the largest building and black smoke billowed into the still winter air. Marcus could see figures moving, stark against the snow, as they carried off their spoils, piling them on to several small carts and a wagon hitched to mules a short distance from the villa.

Marcus galloped down the far side of the rise to the flat road approaching the farm, not much more than half a mile away. The wind roared in his ears and his heart was beating wildly with excitement. Immediately ahead, the horses of Festus and Caesar were kicking up a spray of snow that made it difficult for him to see beyond them. He urged his mount on, steering it to one side, then saw the distant figures scrambling into activity as they spotted the horsemen charging towards them.

‘Don’t let them escape!’ Caesar shouted. ‘I want prisoners!’