Another soldier was on the other side of the princeps and held out a spear. Trajan took it and leaned back to slip it into the long quiver suspended from the rear horn on the right side of his saddle. He held out his hand for another weapon.

‘Oh shit,’ someone said under their breath. Hadrian guessed that it was Bruttius Praesens, the new legatus of Legio VI Ferrata, no doubt regretting the impulse to speak up when the emperor had invited his staff to join him in a spot of practice.

‘Wonder if he’ll try for three?’ Quietus drawled, without looking at Praesens, but it seemed that the princeps was content with two throwing spears. ‘Good to see he had the sense to pick a light little mare,’ he added once this became clear, and gave a sideways glance at Hadrian and Praesens, both of whom were on taller horses from the senior turma of the ala on parade.

‘Don’t pay attention to the nasty man,’ Hadrian cooed into the ear of his mare. He was quite fond of big horses, but had chosen this one from those on offer simply because there was something he liked about her, and that was as good a reason as any. ‘You’re far more lovely than his little gelding.’ Hadrian stroked the horse’s mane.

‘Do you need some privacy?’ Quietus asked. ‘Praesens and I can wander off if you like.’

Praesens’ eyes flicked nervously between the two men, until they both chuckled. Trajan had exiled his uncle, Laberius Maximus, just a few years ago and it was only now that the nephew had received any sign of favour.

Trumpets sounded and a hush spread over the exercise field, apart from the sighing of the wind and the little noises of shuffling and pawing the ground inevitable when more than two thousand horsemen were paraded.

Trajan raised his right arm, the spear pointing straight up into the air. The princeps was handsome enough by Roman standards, his limbs muscular and his chest broad, even though he was of no more than average height. Hadrian suspected that Trajan’s fondness for smaller horses, like the one he had chosen today, was deliberate, for when mounted it made him appear taller. His seat was good, as per regulation, with back straight and heels a little back. His borrowed shield was oval, the field red and decorated with double wreaths probably to show the ala’s record as bistorquata – twice awarded a unit battle honour. The helmet fitted well, even if it looked odd combined with the solid iron cuirass worn only by senior officers.

Trajan walked his horse in a tight circle, making sure it was warmed up as was usual before any drill, even though a trooper had already made sure that the animal was ready. The hush continued, for he had made it known that there was to be no fuss unless he had earned it. Hadrian and the other two came forward and took position behind him, allowing more space than was usual. Ahead of the emperor was an open, carefully smoothed track some thirty paces wide. On either side stood the serried ranks of cavalrymen, parading by turma each with its own standard. Weapons, armour, and every metal fitting on the harnesses were polished to a high sheen, so that the afternoon sun glistened and sparkled off the three ranks of mounted soldiers. Hadrian hoped that none of their horses would shy or panic at the sight when each made the ride, but there was nothing to be done. It was too late to ask for one of the chamfrons worn with the full ceremonial equipment, fitted with dome-like coverings for the horse’s eyes, the metal like a grill so that the animal could see enough straight ahead, but little to the sides; too late, and perhaps it would only have made things worse. You never quite knew with horses. People were so much more predictable.