The decurion was a good-looking man, immaculately turned out, and had not been chosen because he was especially bright. Like the others he let the warmth of the sunny afternoon and the steady rhythm of horses and the jingle of harness and equipment lull his senses. Hardly anyone spoke, and they walked along as the hours passed, conscious that a dozen picked Batavians had little to fear on a road like this.

It was the coach driver who spotted the dark smoke rising away to the west and called out. That was far behind them, which meant that turning back would probably take them towards the threat.

‘We keep going,’ the decurion said. ‘Keep your eyes open, boys.’ He sent a man to ride one hundred paces ahead and another to follow a similar distance behind the coach.

Flies continued to plague them and the steady buzzing added to the warmth of the afternoon to make them sleepy. The shade of a patch of oaks was cool and very welcome, even if it did nothing to hold back the swarms of insects. The road came out into the open, before twisting to find a gentler path down into a gully and up the other side. Beyond that it wove through a long wood, the tree branches sometimes touching as they closed over the road. The decurion knew the place well and wanted to get past it as fast as they could.

The driver was good and took the coach carefully down the slope, reining the mules back when they tried to rush up the far bank. The carriage was high, not really designed for paths like this, and it would be all too easy to tip it or break a wheel.

‘We need to be quick,’ the decurion called back to him as the driver eased the team and coach up on to the flat. The decurion could not see the man he had sent ahead, because the track turned sharply as it went into the trees.

A flick of the whip put the four mules into a trot and they hurried on. The woods were on either side, the trees a good javelin throw away from the road at this point, but pressing nearer up ahead, where the path turned again after about forty paces. There was no sign of the leading rider.

‘Bellicus!’ the decurion called out. The man was not doing much good if he could not see him.